Rotary compressor

ABSTRACT

A rotary compressor is disclosed. A back pressure pocket among a plurality of back pressure pockets closest to a discharge port disposed in at least one of main bearing or sub bearing is radially spaced from an inner circumferential surface of a bearing hole, and communicates with an inner space of a casing through a back pressure passage formed through at least one of the main bearing or the sub bearing. Accordingly, the back pressure pocket closest to the discharge port may strongly support a vane passing near a reference point toward a cylinder while forming a discharge pressure, or a super discharge pressure higher than the discharge pressure. This may suppress or prevent chattering of the vane near the reference point to reduce vibration noise while suppressing or preventing wear between the vane and the cylinder to enhance compression efficiency. This may also suppress or prevent leakage between compression chambers, thereby preventing delay of initial startup of the compressor.

CROSS-REFERENCE TO RELATED APPLICATION(S)

Pursuant to 35 U.S.C. § 119(a), this application claims the benefit of the earlier filing date and the right of priority to Korean Patent Application No. 10-2022-0053183, filed in Korea on Apr. 29, 2022, the contents of which are incorporated by reference herein in their entirety.

BACKGROUND 1. Field

A vane rotary compressor in which a vane is slidably inserted into a rotating roller is disclosed herein.

2. Background

A rotary compressor may be divided into two types, namely, a type in which a vane is slidably inserted into a cylinder to come in contact with a roller, and another type in which a vane is slidably inserted into a roller to come in contact with a cylinder. In general, the former is called a roller eccentric rotary compressor (hereinafter, referred to as a “rotary compressor”), and the latter is referred to as a vane concentric rotary compressor (hereinafter, referred to as a “vane rotary compressor”).

As for a rotary compressor, a vane inserted in a cylinder is pulled out toward a roller by elastic force or back pressure to come into contact with an outer circumferential surface of the roller. On the other hand, for a vane rotary compressor, a vane inserted in a roller rotates together with the roller, and is pulled out by centrifugal force and back pressure to come into contact with an inner circumferential surface of a cylinder.

A rotary compressor independently forms compression chambers as many as the number of vanes per revolution of a roller, and the compression chambers simultaneously perform suction, compression, and discharge strokes. On the other hand, a vane rotary compressor continuously forms compression chambers as many as the number of vanes per revolution of a roller, and each compression chamber sequentially performs suction, compression, and discharge strokes. Accordingly, the vane rotary compressor has a higher compression ratio than the rotary compressor. Therefore, the vane rotary compressor is more suitable for high pressure refrigerant, such as R32, R410a, and CO₂, which have low ozone depletion potential (ODP) and global warming index (GWP).

Such a vane rotary compressor is disclosed in each of Japanese Laid-Open Patent Application No. JP2013-213438A (hereinafter “Patent Document 1”), (U.S Patent Publication No. 2015/0132168 A1 (hereinafter “Patent Document 2), and Korean Patent Application No. 10-2020-0057542 (hereinafter “Patent Document 3), which are hereby incorporated by reference. The vane rotary compressor disclosed in each of these patent documents discloses a structure in which a plurality of vanes is slidably inserted into a rotating roller.

In addition, in these patent documents, a back pressure chamber is formed at a rear end of each vane and communicates with back pressure pockets provided in a main bearing and a sub bearing. The back pressure pocket is divided into a first pocket forming an intermediate pressure and a second pocket forming a discharge pressure or an intermediate pressure close to the discharge pressure. Based on a reference point (proximity, proximal or contact point) at which a roller is close to a cylinder, the first pocket communicates with a back pressure chamber located at an upstream side, and the second pocket communicates with another back pressure chamber located at a downstream side.

However, in the related art vane rotary compressor, a compression cycle is shortened and a pressure difference between front and rear sides of a vane increases. This may make a behavior of the vane unstable, and cause so-called vane chattering, that is, a front surface of the vane collides with an inner circumferential surface of a cylinder. This may occur intensively in the vicinity of a reference point where a pressure of a compression chamber is highest, that is, to which a final discharge port is adjacent. This may cause wear of the inner circumferential surface of the cylinder or the front surface of the vane in the vicinity of the reference point. As a result, vibration noise may increase in the vicinity of the reference point and leakage between compression chambers may occur due to wear between the cylinder and the vane. This may cause an increase in specific volume of suction refrigerant and an occurrence of suction loss, thereby lowering efficiency of the compressor.

In addition, in the related art vane rotary compressor, chattering in the vicinity of the reference point may severely occur at an initial startup (the beginning of an operation) of the compressor, which may further lower the efficiency of the compressor and even delay an air conditioning effect of an air conditioning apparatus employing the compressor.

In the related art vane rotary compressor, the vane reciprocates while an axial side surface thereof is in contact with a main bearing and/or sub bearing. During this process, the vane may be excessively brought into contact with the main bearing and/or sub bearing, which may cause the vane to reciprocate discontinuously. Then, the vane may chatter more severely, thereby aggravating damages of the cylinder and/or vane and the suction loss.

Those problems become more serious when a high-pressure refrigerant, such as R32, R410a, or CO₂, is used. In more detail, when the high-pressure refrigerant is used, the same level of cooling capability may be obtained as that obtained when using a relatively low-pressure refrigerant, such as R134a, even though a volume of each compression chamber is reduced by increasing the number of vanes. However, if the number of vanes is increased, a compression cycle between the vane and the cylinder is shortened by that much, and the chattering of the vane in the vicinity of the reference point may be aggravated. This may be even worse under a low-temperature heating condition, a high-pressure ratio condition (Pd/Ps≥6), and a high-speed operating condition (above 80 Hz).

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will be described in detail with reference to the following drawings in which like reference numerals refer to like elements, and wherein:

FIG. 1 is a cross-sectional view illustrating one embodiment of a vane rotary compressor according to an embodiment;

FIG. 2 is an exploded perspective view illustrating a portion of a compression part in FIG. 1 ;

FIG. 3 is an assembled planar view of the compression part in FIG. 2 ;

FIG. 4 is an exploded perspective view of a sub bearing and a rotational shaft in FIG. 2 ;

FIG. 5 is an assembled planar view of FIG. 4 ;

FIG. 6 is a sectional view taken along the line “VI-VI” of FIG. 5 ;

FIG. 7 is a sectional view taken along the line “VII-VII” of FIG. 5 ;

FIG. 8 is a perspective view of a communication groove of FIG. 2 according to another embodiment;

FIG. 9 is a cross-sectional view illustrating a process of supplying oil to a back pressure pocket in a rotary compressor in accordance with an embodiment;

FIG. 10 is a graph showing comparison results of a vane contact force for each rotational angle of a vane rotary compressor according to an embodiment with that of the related art;

FIG. 11 is a perspective view of a back pressure passage unit of FIG. 2 according to another embodiment;

FIG. 12 is an assembled cross-sectional view of FIG. 11 ;

FIG. 13 is an exploded perspective view of a back pressure passage unit according to still another embodiment;

FIG. 14 is an assembled cross-sectional view of FIG. 13 ;

FIG. 15 is an exploded perspective view of the compression part in FIG. 1 according to another embodiment;

FIG. 16 is a planar view illustrating a main bearing in FIG. 15 ;

FIG. 17 is a planar view illustrating a sub bearing in FIG. 15 ;

FIG. 18 is an assembled cross-sectional view of FIG. 15 ;

FIG. 19 is a perspective view of a lubricating portion in FIG. 15 according to another embodiment;

FIG. 20 is a cross-sectional view of FIG. 19 ;

FIG. 21 is a perspective view of the lubricating portion in FIG. 15 according to still another embodiment; and

FIG. 22 is a cross-sectional view of FIG. 21 .

DETAILED DESCRIPTION

Description will now be given of a vane rotary compressor according to embodiments disclosed herein, with reference to the accompanying drawings.

Embodiments describe a structure in which a vane spring is disposed in a roller, which may be equally applied to a vane rotary compressor in which a vane is slidably inserted into a roller. For example, embodiments may be equally applicable not only to a vane rotary compressor having an elliptical (hereinafter, asymmetric elliptical) cylinder, an inner circumferential surface of which has a plurality of curvatures, but also to a vane rotary compressor having a circular cylinder, an inner circumferential surface of which has one curvature. The embodiments may also be equally applicable to a vane rotary compressor in which a vane slot into which a vane is slidably inserted is inclined by a predetermined angle with respect to a radial direction of a roller, as well as a vane rotary compressor in which a vane slot is formed in a radial direction of a roller. Hereinafter, an example in which an inner circumferential surface of a cylinder has an asymmetric elliptical shape and a vane slot is inclined with respect to a radial direction of a roller will be described as a representative example.

FIG. 1 is a cross-sectional view embodiments of a vane rotary compressor according to an embodiment. FIG. 2 is an exploded perspective view illustrating a compression part in FIG. 1 , and FIG. 3 is an assembled planar view of the compression part in FIG. 2 .

Referring to FIG. 1 , a vane rotary compressor according to this embodiment may include a casing 110, a drive motor 120, and a compression part or portion 130. The drive motor 120 may be installed in an upper inner space 110 a of the casing 110, and the compression part 130 may be installed in a lower inner space 110 a of the casing 110. The drive motor 120 and the compression part 130 may be connected through a rotational shaft 123.

The casing 110 that defines an outer appearance of the compressor may be classified as a vertical type and a horizontal type according to a compressor installation method. As for the vertical type casing, the drive motor 120 and the compression part 130 are disposed at upper and lower sides in an axial direction, respectively. As for the horizontal type casing, the drive motor 120 and the compression part 130 are disposed at left and right or lateral sides, respectively. The casing according to this embodiment may be illustrated as the vertical type. However, embodiments may be equally applied to a case in which the casing is arranged horizontally.

The casing 110 may include an intermediate shell 111 having a cylindrical shape, a lower shell 112 covering a lower end of the intermediate shell 111, and an upper shell 113 covering an upper end of the intermediate shell 111. The drive motor 120 and the compression part 130 may be inserted into the intermediate shell 111 to be fixed thereto, and a suction pipe 115 may penetrate through the intermediate shell 111 to be directly connected to the compression part 130. The lower shell 112 may be coupled to the lower end of the intermediate shell 111 in a sealing manner, and an oil storage space 110 b in which oil to be supplied to the compression part 130 is stored may be formed below the compression part 130. The upper shell 113 may be coupled to the upper end of the intermediate shell 111 in a sealing manner, and an oil separation space 110 c may be formed above the drive motor 120 to separate oil from refrigerant discharged from the compression part 130.

The drive motor 120 that constitutes a motor supplies power to drive the compression part 130. The drive motor 120 may include a stator 121, a rotor 122, and a rotational shaft 123.

The stator 121 may be fixedly inserted into the casing 110. The stator 121 may be fixed to an inner circumferential surface of the casing 110 in a shrink-fitting manner, for example. For example, the stator 121 may be press-fitted into an inner circumferential surface of the intermediate shell 111.

The rotor 122 may be rotatably inserted into the stator 121, and the rotational shaft 123 may be press-fitted into a center of the rotor 122. Accordingly, the rotational shaft 123 rotates concentrically together with the rotor 122.

An oil supply passage 125 having a hollow hole shape may be formed in a central portion of the rotational shaft 123, and first and second oil supply holes 126 a and 126 b and a first back pressure hole 138 a may be formed through a middle portion of the oil supply passage 125 toward an outer circumferential surface of the rotational shaft 123. The first oil supply hole 126 a may be formed to belong to a range of a main bush portion 1312 described hereinafter, and the second oil supply hole 126 b and the first back pressure hole 138 a may be formed to belong to a range of a sub bearing portion 1322.

Each of the first oil supply hole 126 a and the second oil supply hole 126 b may be provided as one in number or as a plurality. This embodiment illustrates an example in which each of the first oil supply hole 126 a and the second oil supply hole 126 b is provided as a plurality along a circumferential direction.

The first back pressure hole 138 a may communicate with a second back pressure hole 138 b described hereinafter. Accordingly, high-pressure oil passing through the first back pressure hole 138 a may be directly supplied to a third sub back pressure pocket 1325 c described hereinafter through the second back pressure hole 138 b. The first back pressure hole 138 a will be described hereafter together with the second back pressure hole 138 b.

An oil pickup 127 may be installed in a middle or lower end of the oil supply passage 125. A gear pump, a viscous pump, or a centrifugal pump may be used for the oil pickup 127, for example. This embodiment illustrates a case in which the centrifugal pump is employed. Accordingly, when the rotational shaft 123 rotates, oil filled in the oil storage space 110 b is pumped up by the oil pickup 127 and suctioned upward along the oil supply passage 125. The oil may be supplied partially to the third sub back pressure pocket 1325 c through the first back pressure hole 138 a, partially to the sub bearing surface 1322 b of the sub bush portion 1322 through the second oil supply hole 126 b, and partially to the main bearing surface 1312 b of the main bush portion 1312 through the first oil supply hole 126 a.

The rotational shaft 123 may include a roller 134 described hereinafter. The roller 134 may extend integrally from the rotational shaft 123 or the rotational shaft 123 and the roller 134 may be separately manufactured and post-assembled to each other. In this embodiment, the rotational shaft 123 is post-assembled by being inserted into the roller 134. For example, a shaft hole 1341 may be formed through a center of the roller 134 in an axial direction and the rotational shaft 123 may be press-fitted into the shaft hole 1341 or coupled to the shaft hole 1341 to be movable in the axial direction. When the rotational shaft 123 is movably coupled to the roller 134 in the axial direction, a rotation preventing unit (not illustrated) may be provided between the rotational shaft 123 and the roller 134 so that the rotational shaft 123 may be locked with respect to the roller 134 in the circumferential direction.

The compression part 130 may include a main bearing 131, a sub bearing 132, a cylinder 133, roller 134, and a vane 135. The main bearing 131 and the sub bearing 132 may be respectively provided at upper and lower parts or portions of the cylinder 133 to define a compression space V together with the cylinder 133. The roller 134 may be rotatably installed in the compression space V, and the vane 135 may be slidably inserted into the roller 134 to divide the compression space V into a plurality of compression chambers.

Referring to FIGS. 1 to 3 , the main bearing 131 may be fixedly installed in the intermediate shell 111 of the casing 110. For example, the main bearing 131 may be inserted into the intermediate shell 111 and welded thereto.

The main bearing 131 may be coupled to an upper end of the cylinder 133 in a close contact manner. Accordingly, the main bearing 131 defines an upper surface of the compression space V, and supports an upper surface of the roller 134 in the axial direction and at the same time supports an upper portion of the rotational shaft 123 in the radial direction.

The main bearing 131 may include a main plate portion 1311 and a main bush portion 1312. The main plate portion 1311 covers an upper part or portion of the cylinder 133 to be coupled thereto, and the main bush portion 1312 axially extends from a center of the main plate portion 1311 toward the drive motor 120 so as to support the upper portion of the rotational shaft 123.

The main plate portion 1311 may have a disk shape, and an outer circumferential surface of the main plate portion 1311 may be fixed to the inner circumferential surface of the intermediate shell 111 in a close contact manner. At least one discharge port 1313 may be formed through the main plate portion 1311 in the axial direction. In this embodiment, a plurality of discharge ports 1313 a, 1313 b, and 1313 c is formed at predetermined distances along the circumferential direction, and a plurality of discharge valves 1361, 1362, 1363 that open and close the respective discharge ports 1313 a, 1313 b, and 1313 c, is disposed on an upper surface of the main plate portion 1311. A discharge muffler 137 having a discharge space (no reference numeral given) to accommodate the plurality of discharge ports 1313 a, 1313 b, 1313 c and discharge valves 1361, 1362, and 1363 may be disposed on an upper side of the main plate portion 1311.

Accordingly, the discharge ports 1313 a, 1313 b, and 1313 c may be formed in the main bearing (or sub bearing) 131, instead of the cylinder 133, which may simplify the structure of the cylinder 133 so as to facilitate processing of the cylinder 133. In addition, a surface pressure between a front surface of the vane 133 in the vicinity of the discharge port 1313 a, 1313 b, 1313 c and the inner circumferential surface of the cylinder 133 facing it may be lowered and constantly maintained at the same time, while chattering of the vane 135 may be reduced so as to suppress wear and vibration noise between the front surface of the vane 135 and the inner circumferential surface of the cylinder 133 facing it.

A main back pressure pocket 1315 may be formed in a lower surface, namely, a main sliding surface 1311 a of the main plate portion 1311 facing the upper surface of the roller 134, of both axial side surfaces of the main plate portion 1311. The main back pressure pocket 1315 may be provided as one in number or may be provided as a plurality along the circumferential direction. In this embodiment, as illustrated in FIGS. 2 and 3 , a plurality of main back pressure pockets 1315 a, 1315 b, and 1315 c is disposed at preset or predetermined distances along a rotational direction of the roller 134 based on a reference point P described hereinafter.

For example, the main back pressure pocket 1315 according to the embodiment may include a first main back pressure pocket 1315 a, a second main back pressure pocket 1315 b, and a third main back pressure pocket 1315 c. The first main back pressure pocket 1315 a, the second main back pressure pocket 1315 b, and the third main back pressure pocket 1315 c may be formed in an arcuate shape and disposed at the preset or predetermined distances in the circumferential direction.

Inner and outer circumferential surfaces of each of the first main back pressure pocket 1315 a, the second main back pressure pocket 1315 b, and the third main back pressure pocket 1315 c may be formed in a circular shape. Or the inner circumferential surface may be formed in a circular shape and the outer circumferential surface may be formed in an elliptical shape in consideration of a vane slot 1343 described hereinafter. This embodiment illustrates an example in which the outer circumferential surface of the first main back pressure pocket 1315 a is formed in an elliptical shape.

The first main back pressure pocket 1315 a, the second main back pressure pocket 1315 b, and the third main back pressure pocket 1315 c may be formed within an outer diameter range of the roller 134. Accordingly, the first main back pressure pocket 1315 a, the second main back pressure pocket 1315 b, and the third main back pressure pocket 1315 c may be isolated from the compression space V. However, the first main back pressure pocket 1315 a, the second main back pressure pocket, and the third main back pressure pocket 1315 c may minutely communicate with each other through a gap between a lower surface, that is, a main sliding surface 1311 a of the main plate portion 1311 and the upper surface of the roller 134 facing each other unless a separate sealing member is provided therebetween.

The first main back pressure pocket 1315 a may form a pressure lower than a pressure formed in the second main back pressure pocket 1315 b, for example, form an intermediate pressure between a suction pressure and a discharge pressure. In other words, oil (refrigerant oil) may pass through a fine passage between a first main bearing protrusion 1316 a described hereinafter and the upper surface of the roller 134 so as to be introduced into the main back pressure pocket 1315 a. The first main back pressure pocket 1315 a may be formed in the range of a compression chamber forming an intermediate pressure in the compression space V. Accordingly, the first main back pressure pocket 1315 a maintains a first intermediate pressure.

The second main back pressure pocket 1315 b forms a pressure higher than the pressure formed in the first main back pressure pocket 1315 a, for example, forms the discharge pressure or a second intermediate pressure between the first intermediate pressure close to the discharge pressure and the discharge pressure. In other words, as the inner circumferential surface of the second main back pressure pocket 1315 b is completely or partially open toward the main bearing hole 1312 a of the main bearing 131, such that oil introduced into the main bearing hole 1312 a through the first oil supply hole 126 a may be introduced into the second main back pressure pocket 1315 b without substantial decompression. The second main back pressure pocket 1315 b may be formed in the range of a compression chamber forming the discharge pressure or a substantial discharge pressure in the compression space V. Accordingly, the second main back pressure pocket 1315 b maintains the discharge pressure or the second intermediate pressure close to the discharge pressure.

The third main back pressure pocket 1315 a forms a pressure higher than the pressure formed in the second main back pressure pocket 1315 b, for example, forms a super discharge pressure higher than the discharge pressure. In other words, the inner circumferential surface of the third main back pressure pocket 1315 c is closed by being spaced apart from the main bearing hole 1312 a, and at the same time, the third main back pressure pocket 1315 c is isolated from the inner space of the casing. The third main back pressure pocket 1315 c may be formed in the range of a compression chamber forming the discharge pressure in the compression space V. Accordingly, the third main back pressure pocket 1315 c maintains the super discharge pressure higher than the discharge pressure. The third main back pressure pocket 1315 c will be described hereinafter together with a third sub back pressure pocket 1325 c described hereinafter.

In addition, a first main bearing protrusion 1316 a, a second main bearing protrusion 1316 b, and a third main bearing protrusion 1316 c may be formed on inner circumferential sides of the first main back pressure pocket 1315 a, the second main back pressure pocket 1315 b, and the third main back pressure pocket 1315 c, respectively, in a manner of extending from the main bearing surface 1312 b of the main bush portion 1312. Accordingly, the first main back pressure pocket 1315 a, the second main bearing protrusion 1316 b, and the third main back pressure pocket 1315 c may be sealed from outside and simultaneously the rotational shaft 123 may be stably supported.

The first main bearing protrusion 1316 a, the second main bearing protrusion 1316 b, and the third main bearing protrusion 1316 c may have a same height or different heights. For example, when the first main bearing protrusion 1316 a, the second main bearing protrusion 1316 b, and the third main bearing protrusion 1316 c have the same height, an oil communication groove (not illustrated) or an oil communication hole (not illustrated) may be formed on an end surface of the second main bearing protrusion 1316 b such that inner and outer circumferential surfaces of the second main bearing protrusion 1316 b may communicate with each other. Accordingly, high-pressure oil (refrigerant oil) flowing into the main bearing surface 1312 b may be introduced into the second main back pressure pocket 1315 b through the oil communication groove (not illustrated) or the oil communication hole (not illustrated).

On the other hand, when the first main bearing protrusion 1316 a, the second main bearing protrusion 1316 b, and the third main bearing protrusion 1316 b have different heights, the height of the second main bearing protrusion 1316 b may be lower than the height of the first main bearing protrusion 1316 a and the height of the third main bearing protrusion 1316 c. Accordingly, high-pressure oil (refrigerant oil) flowing into the main bearing hole 1312 a may be introduced into the second main back pressure pocket 1315 b by flowing over the second main bearing protrusion 1316 b.

Referring to FIGS. 1 to 3 , the sub bearing 132 may be coupled to a lower end of the cylinder 133 in a close contact manner. Accordingly, the sub bearing 132 defines a lower surface of the compression space V, and supports a lower surface of the roller 134 in the axial direction and at the same time supports a lower portion of the rotational shaft 123 in the radial direction.

The sub bearing 132 may include a sub plate portion 1321 and the sub bush portion 1322. The sub plate portion 1321 covers a lower part or portion of the cylinder 133 to be coupled thereto, and the sub bush portion 1322 axially extends from a center of the sub plate portion 1321 toward the lower shell 112 so as to support the lower portion of the rotational shaft 123.

The sub plate portion 1321 may have a disk shape like the main plate portion 1311. An outer circumferential surface of the sub plate portion 1321 may be spaced apart from the inner circumferential surface of the intermediate shell 111.

A sub back pressure pocket 1325 may be formed on an upper surface of both axial side surfaces of the sub plate portion 1321, namely, a sub sliding surface 1321 a of the sub plate portion 1321 facing the lower surface of the roller 134, to correspond to the main back pressure pocket 1315. The sub back pressure pocket 1325 may be provided as one in number or may be provided as a plurality. In this embodiment, as illustrated in FIGS. 2 and 3 , a plurality of sub back pressure pockets 1325 a, 1325 b, and 1325 c may be disposed at preset or predetermined distances along the circumferential direction.

For example, the sub back pressure pocket 1325 may include a first sub back pressure pocket 1325 a, a second sub back pressure pocket 1325 b, and a third sub back pressure pocket along the rotational direction of the roller 134 on the basis of the reference point P. These first sub back pressure pocket 1325 a, second sub back pressure pocket 1325 b, and third sub back pressure pocket 1325 c may be formed to symmetric to the first main back pressure pockets 1315 a, the second main back pressure pocket 1315 b, and the third main back pressure pocket 1315 c, respectively, based on the roller 134.

In other words, the first sub back pressure pocket 1325 a and the first main back pressure pocket 1315 a may be symmetric to each other, the second sub back pressure pocket 1325 b and the second main back pressure pocket 1315 b may be symmetric to each other, and the third sub back pressure pocket 1325 c and the third main back pressure pocket 1315 c may be symmetric to each other. Accordingly, a first sub bearing protrusion 1326 a may be formed on an inner circumferential side of the first sub back pressure pocket 1325 a, a second sub bearing protrusion 1326 b on an inner circumferential side of the second sub back pressure pocket 1325 b, and a third sub bearing protrusion 1326 c on an inner circumferential side of the third sub back pressure pocket 1325 c, respectively.

Description of the first sub back pressure pocket 1325 a, the second sub back pressure pocket 1325 b, and the third sub back pressure pocket 1325 c may be the same as the description of the first main back pressure pocket 1315 b, the second main back pressure pocket 1315 b, and the third main back pressure pocket 1315 c, and thus, repetitive description has been omitted. Also, description of the first sub bearing protrusion 1326 a, the second sub bearing protrusion 1326 b, and the third sub bearing protrusion 1326 c may be the same as the description of the first main bearing protrusion 1316 b, the second main bearing protrusion 1315 b, and the third main bearing protrusion 1316 c, and thus, repetitive description has been omitted.

However, in some cases, the first sub back pressure pocket 1325 a, the second sub back pressure pocket 1325 b, and the third sub back pressure pocket 1325 c may be asymmetric to the first main back pressure pocket 1315 a, the second main back pressure pocket 1315 b, and the third main back pressure pocket 1315 c, respectively, based on the roller 134. For example, the first sub back pressure pocket 1325 a may be deeper than the first main back pressure pocket 1315 a, the second sub back pressure pocket 1325 b deeper than the second main back pressure pocket 1315 b, and the third sub back pressure pocket 1325 c deeper than third main back pressure pocket 1315 c, respectively.

The third sub back pressure pocket 1325 c forms a pressure higher than a pressure formed in the second sub back pressure pocket 1325 b, that is, a super discharge pressure, like the third main back pressure pocket 1315 c. The third sub back pressure pocket 1325 c will be described hereinafter together with the third main back pressure pocket 1315 c.

Although not illustrated, only one of the main back pressure pocket [1315 a, 1315 b, 1315 c] and the sub back pressure pocket [1325 a, 1325 b, 1325 c] may be formed. In this case, the sub back pressure pockets [1325 a, 1325 b, 1325 c] relatively adjacent to the oil storage space may be formed.

In addition, the second back pressure hole 138 b described above is formed in the sub bush portion 1322. For example, one (first) end of the second back pressure hole 138 b may be open toward the inner circumferential surface of the sub bush portion 1322 to communicate with the first back pressure hole 138 a of the rotational shaft 123, and another (second) end of the second back pressure hole 138 b may be open toward a bottom surface of the third sub back pressure pocket 1325 c to communicate with the third sub back pressure pocket 1325 c. Accordingly, oil that flows inward between the outer circumferential surface of the rotational shaft 123 and the inner circumferential surface of the sub bush portion 1322 through the first back pressure hole 138 a is directly introduced into the third sub back pressure pocket 1325 c through the second back pressure hole 138 b. The oil forms a super discharge pressure together with a corresponding back pressure chamber 1344 in the third sub back pressure pocket 1325 c, which is almost closed except for the second back pressure hole 138 b, when the vane 135 passing through the third sub back pressure pocket 1325 c moves backward. This will be described again hereinafter.

The discharge port 1313 may be formed in the main bearing 131 as described above. However, the discharge port 1313 may be formed in the sub bearing 132, formed in each of the main bearing 131 and the sub bearing 132, or formed by penetrating between inner and outer circumferential surfaces of the cylinder 133. This embodiment describes an example in which the discharge ports 1313 are formed in the main bearing 131.

The discharge port 1313, as aforementioned, may be provided as a plurality 1313 a, 1313 b, and 1313 c disposed at preset or predetermined distances along a compression-proceeding direction (or the rotational direction of the roller), and the plurality of discharge ports 1313 a, 1313 b, and 1313 c may be disposed at preset or predetermined distances in the circumferential direction, namely, the rotational direction of the roller 134.

In addition, the plurality of discharge ports 1313 a, 1313 b, and 1313 c may be formed individually, but may also be formed as pairs, as illustrated in this embodiment. For example, starting from a discharge port which is the most adjacent to the proximal portion 1332 a, the first discharge port 1313 a, the second discharge port 1313 b, and the third discharge port 1313 c of the discharge port 1313 may be sequentially arranged. Accordingly, as the compression space V approaches the reference point P, a discharge area of the discharge port 1313 may be secured even if a distance between the inner circumferential surface 1332 of the cylinder 133 and the outer circumferential surface 1342 of the roller 134 decreases. This can allow smooth discharge of compressed refrigerant and suppress or prevent overcompression and/or pressure pulsation.

Although not illustrated, when vane slots 1343 a, 1343 b, and 1343 c described hereinafter are formed at unequal intervals, a circumferential length of each compression chamber V1, V2, V3 may be different, and the plurality of discharge ports may communicate with one compression chamber or one discharge port may communicate with the plurality of compression chambers.

Referring to FIGS. 1 to 3 , the cylinder 133 according to this embodiment may be in close contact with a lower surface of the main bearing 131 and be coupled to the main bearing 131 by, for example, a bolt together with the sub bearing 132. Accordingly, the cylinder 133 may be fixedly coupled to the casing 110 by the main bearing 131.

The cylinder 133 may be formed in an annular shape having a hollow space in its center to define the compression space V. The hollow space may be sealed by the main bearing 131 and the sub bearing 132 to define the compression space V, and the roller 134 described hereinafter may be rotatably coupled to the compression space V. The cylinder 133 may be provided with a suction port 1331 penetrating from an outer circumferential surface to an inner circumferential surface thereof. However, the suction port may alternatively be formed through the main bearing 131 or the sub bearing 132.

The suction port 1331 may be formed at one (first) side of the reference point P described hereinafter in the circumferential direction. The discharge port 1313 described above may be formed through the main bearing 131 at another (second) side of the reference point P in the circumferential direction that is opposite to the suction port 1331.

The inner circumferential surface 1332 of the cylinder 133 may be formed in an elliptical shape. The inner circumferential surface 1332 of the cylinder 133 according to this embodiment may be formed in an asymmetric elliptical shape in which a plurality of ellipses, for example, four ellipses having different major and minor ratios are combined to have two origins.

The inner circumferential surface 1332 of the cylinder 133 according to the embodiment may be defined to have a first origin O which is a center of the roller 134 or a center of rotation of the roller 134 (an axial center or a diameter center of the cylinder) and a second origin O′ biased from the first origin O toward the reference point P. An X-Y plane formed around the first origin O may define a third quadrant Q3 and a fourth quadrant Q4, and an X-Y plane formed around the second origin O′ may define a first quadrant Q1 and a second quadrant Q2. The third quadrant Q3 may be formed by a third ellipse, the fourth quadrant Q4 may be formed by a fourth ellipse, the first quadrant Q1 may be formed by the first ellipse, and the second quadrant Q2 may be formed by the second ellipse.

In addition, the inner circumferential surface 1332 of the cylinder 133 may include a proximal portion 1332 a, a remote portion 1332 b, and a curved portion 1332 c. The proximal portion 1332 a is a portion closest to the outer circumferential surface 1341 (or the center of rotation) of the roller 134, the remote portion 1332 b is a portion farthest away from the outer circumferential surface 1342 of the roller 134, and the curved portion 1332 c is a portion connecting the proximal portion 1332 a and the remote portion 1332 b. The proximal portion 1332 a may also be defined as the reference point P, and the first quadrant Q1 and the fourth quadrant Q4 may be divided based on the proximal portion 1332 a. The suction port 1331 may be formed in the first quadrant Q1 and the discharge port 1313 may be formed in the fourth quadrant Q4, based on the proximal portion 1332 a. Accordingly, when the vane 1351, 1352, 1353 passes the reference point P, a compression surface of the roller 134 in the rotational direction may receive the suction pressure as a low pressure but an opposite compression rear surface may receive the discharge pressure as a high pressure. Then, while passing the reference point P, the roller 134 may receive a greatest fluctuating pressure between a front surface 1351 a, 1352 a, 1353 a of each vane 1351, 1352, 1353 that comes in contact with the inner circumferential surface of the cylinder 133 and a rear surface 1351 b, 1352 b, 1353 b of each vane 1351, 1352, 1353 that faces the back pressure chamber 1344 a, 1344 b, 1344 c. This may cause significant tremor of the vane 1351, 1352, 1353.

Referring to FIGS. 1 to 3 , the roller 134 according to the embodiment may be rotatably disposed in the compression space V of the cylinder 133, and the plurality of vanes 1351, 1352, 1353 described hereinafter may be inserted in the roller 134 at predetermined intervals along the circumferential direction. Accordingly, the compression space V may be partitioned into as many compression chambers as the number of the plurality of vanes 1351, 1352, and 1353. This embodiment illustrates an example in which the plurality of vanes 1351, 1352, and 1353 are three, and thus, the compression space V is partitioned into three compression chambers V1, V2, and V3.

As described above, the roller 134 may extend integrally from the rotational shaft 123 or may be manufactured separately from the rotational shaft 123 and then post-assembled to the rotational shaft 123. This embodiment will be described based on an example in which the roller is post-assembled to the rotational shaft 123.

However, even when the roller 134 extends integrally from the rotational shaft 123, the rotational shaft 123 and the roller 134 may be formed similarly to those in this embodiment, and the basic operating effects thereof may also be substantially the same as those of this embodiment. However, when the roller 134 is post-assembled to the rotational shaft 123 as in this embodiment, the roller 134 may be formed of a material different from the rotational shaft 123, for example, a material lighter than that of the rotational shaft 123. This may facilitate processing of the roller body 134, and simultaneously reduce a weight of a rotating body including the roller 134, thereby enhancing efficiency of the compressor.

The roller 134 according to this embodiment may be formed as a single body, that is, an integral roller having one roller body (no reference numeral). However, the roller 134 may not be necessarily formed as the integral roller. For example, the roller 134 may be formed as a separable roller which is separated into a plurality of roller bodies (no reference numeral). This will be described hereinafter in another embodiment. In this embodiment, an integral roller 134 configured as a single body will be described as an example.

Referring to FIGS. 1 to 3 , the roller 134 according to the embodiment may be formed in an annular shape with a shaft hole 1341 at the center thereof. For example, the roller 134 may have inner and outer circumferential surfaces, and the inner and outer circumferential surfaces of the roller 134 may be formed in a circular shape. However, the inner circumferential surface of the roller 134 may be formed as a continuous surface, whereas the outer circumferential surface of the roller 134 may be formed as a discontinuous surface due to an open surface of the vane slot 1343 disposed thereon. The vane slot 1343 may be provided as one in number or may be provided as a plurality. This embodiment illustrates an example in which a plurality of vane slots 1343 a, 1343 b, and 1343 c is formed at preset or predetermined distances in the circumferential direction. Accordingly, the outer circumferential surface of the roller 134 may be formed to have discontinuous surfaces as many as the number of vane slots 1343 a, 1343 b, and 1343 c.

Also, the rotational center Or of the roller 134 is coaxially located with an axial center (no reference numeral) of the rotational shaft 123, and the roller 134 rotates concentrically with the rotational shaft 123. However, as described above, as the inner circumferential surface 1332 of the cylinder 133 is formed in the asymmetric elliptical shape biased in a specific direction, the rotational center Or of the roller 134 may be eccentrically disposed with respect to an outer diameter center Oc of the cylinder 133. Accordingly, the outer circumferential surface 1342 of one side of the roller 134 is substantially brought into contact with the inner circumferential surface 1332 of the cylinder 133, precisely, the proximal portion 1332 a, thereby defining the reference point P.

The reference point P may be formed in the proximal portion 1332 a as described above. Accordingly, an imaginary line passing through the reference point P may correspond to a minor axis of an elliptical curve defining the inner circumferential surface 1332 of the cylinder 133.

The roller 134 may have the plurality of vane slots 1343 a, 1343 b, and 1343 c, into which the vanes 1351, 1352, and 1353 described hereinafter are slidably inserted, respectively. The plurality of vane slots 1343 a, 1343 b, and 1343 c may be formed at preset or predetermined intervals along the circumferential direction. The outer circumferential surface 1342 of the roller 134 may have open surfaces that are open in the radial direction. A back pressure chamber 1344 (1344 a, 1344 b, and 1344 c), which will be described hereinafter, may be formed in inner end portions that are opposite to the open surfaces, so as to have a closed shape in the radial direction.

The plurality of vane slots 1343 a, 1343 b, and 1343 c may be defined as first vane slot 1343 a, second vane slot 1343 b, and third vane slot 1343 c along a compression-progressing direction (the rotational direction of the roller). The first vane slot 1343 a, the second vane slot 1343 b, and the third vane slot 1343 c may be formed at uniform or non-uniform intervals along the circumferential direction.

For example, each of the vane slots 1343 a, 1343 b, and 1343 c may be inclined by a preset or predetermined angle with respect to the radial direction, so as to secure a sufficient length of each of the vanes 1351, 1352, and 1353. Accordingly, when the inner circumferential surface 1332 of the cylinder 133 is formed in the asymmetric elliptical shape, even if a distance from the outer circumferential surface 1342 of the roller 134 to the inner circumferential surface 1332 of the cylinder 133 increases, the separation of the vanes 1351, 1352, and 1353 from the vane slots 1343 a, 1343 b, and 1343 c may be suppressed or prevented, which may result in enhancing the design freedom for the inner circumferential surface 1332 of the cylinder 133 as well as that of the roller 134.

A direction in which the vane slots 1343 a, 1343 b, and 1343 c are inclined may be a reverse direction to the rotational direction of the roller 134. That is, the front surfaces 1351 a, 1352 a, and 1353 a of the vanes 1351, 1352, and 1353 in contact with the inner circumferential surface 1332 of the cylinder 133 may be tilted toward the rotational direction of the roller 134. This may be advantageous in that a compression start angle may be formed ahead in the rotational direction of the roller 134 so that compression may start quickly.

The back pressure chamber 1344 is formed in a central portion of the roller 134, that is, in an inner end of the vane slot 1343. The back pressure chamber 1344 extends laterally from the vane slot 1343. Accordingly, the back pressure chamber 1344 communicates with the vane slot 1343 to form a kind of back pressure space to support the vane 135 slidably inserted into the vane slot 1343 toward the inner circumferential surface 1332 of the cylinder 133.

The back pressure chamber 1344 is formed as many as the number of vane slots 1343. The back pressure chamber 1344 according to the embodiment includes three back pressure chambers 1344 a, 1344 b, and 1344 c, like the vane slots 1343 a, 1343 b, and 1343 c, and the three back pressure chambers 1344 a 1344 b, and 1344 c are formed in one-to-one correspondence with the three vane slots 1343 a, 1343 b, and 1343 c.

The plurality of back pressure chambers 1344 a, 1344 b, and 1344 c may accommodate oil (or refrigerant) at the discharge pressure or intermediate pressure toward the rear sides of the vanes 1351, 1352, and 1353, that is, rear surfaces 1351 c, 1352 c, and 1353 c of the vanes 1351, 1352, 1353. The vanes 1351, 1352, and 1353 may be pressed toward the inner circumferential surface of the cylinder 133 by the pressure of the oil (or refrigerant). Hereinafter, a direction toward the inner circumferential surface of the cylinder based on a motion direction of the vane may be defined as the front, and an opposite side to the direction may be defined as the rear.

Although not illustrated, the plurality of vane slots 1343 a, 1343 b, and 1343 c may be formed in the radial direction, that is, radially with respect to the rotational center Or of the roller 134. Operating effects to be obtained by the configuration are similar to those in the following embodiment in which the plurality of vane slots 1343 a, 1343 b, and 1343 c is inclined with respect to the rotational center Or of the roller 134, which will be described hereinafter, so repetitive description thereof has been omitted.

The plurality of back pressure chamber 1342 a, 1342 b, and 1342 c may be hermetically sealed by the main bearing 131 and the sub bearing 132. In other words, the back pressure chambers 1344 a, 1344 b, and 1344 c may independently communicate with the back pressure pockets 1315 and 1325 and may also communicate with each other by the back pressure pockets 1315 and 1325. In this embodiment, an example in which some back pressure chambers 1344 communicate with each other by other back pressure pockets 1315 and 1325 is illustrated.

More specifically, as each of the plurality of back pressure chambers 1344 a, 1344 b, and 1344 c penetrates in the axial direction, one (first) end of each of the back pressure chambers 1344 a, 1344 b, and 1344 c in the axial direction communicates with the main back pressure pocket 1315 a, 1315 b, 1315 c and another (second) end of each of the back pressure chambers 1344 a, 1344 b, and 1344 c in the axial direction communicates with the sub back pressure pocket 1325 a, 1325 b, 1325 c. Accordingly, oil that passes through both of the back pressure pockets 1315 and 1325 is filled in each of the back pressure chambers 1344 a, 1344 b, and 1344 c. Accordingly, theoretically, internal pressure (back pressure) of the back pressure chamber 1344 may be understood to be the same as internal pressure of each back pressure pocket 1315 and 1325. Hereinafter, the back pressure may also be described as pressure of the back pressure chamber 1344 and pressure of the back pressure pockets 1315 and 1325.

Referring to FIGS. 1 to 3 , the vane 135 according to the embodiment may be provided as a plurality to be individually inserted into the plurality of vane slots 1343 a, 1343 b, and 1343 c. In other words, the plurality of vanes 1351, 1352, and 1353 may be slidably inserted into the respective vane slots 1343 a, 1343 b, and 1343 c. Accordingly, the plurality of vanes 1351, 1352, and 1353 may have substantially the same shape as the respective vane slots 1343 a, 1343 b, and 1343 c.

For example, the plurality of vanes 1351, 1352, 1353 may be defined as first vane 1351, second vane 1352, and third vane 1353 along the rotational direction of the roller 134. The first vane 1351 may be inserted into the first vane slot 1343 a, the second vane 1352 into the second vane slot 1343 b, and the third vane 1353 into the third vane slot 1343 c, respectively.

The plurality of vanes 1351, 1352, and 1353 may have substantially the same shape. For example, the plurality of vanes 1351, 1352, and 1353 may each be formed in a substantially rectangular parallelepiped shape, and the front surfaces 1351 a, 1352 a, 1353 a of the vanes 1351, 1352, and 1353 in contact with the inner circumferential surface 1332 of the cylinder 133 may be curved in the circumferential direction. Accordingly, the front surfaces 1351 a, 1352 a, and 1353 a of the vanes 1351, 1352, and 1353 may come into line-contact with the inner circumferential surface 1332 of the cylinder 133, thereby reducing friction loss.

Hereinafter, operation of the vane rotary compressor with a hybrid cylinder will be described.

That is, when power is applied to the drive motor 120, the rotor 122 of the drive motor 120 and the rotational shaft 123 coupled to the rotor 122 rotate together, causing the roller 134 coupled to the rotational shaft 123 or integrally formed therewith to rotate together with the rotational shaft 123. The plurality of vanes 1351, 1352, and 1353 is drawn out from the respective vane slots 1343 a, 1343 b, and 1343 c by centrifugal force generated by rotation of the roller 134, so as to be brought into contact with the inner circumferential surface 1332 of the cylinder 133.

Then, the compression space V of the cylinder 133 is divided into compression chambers (including a suction chamber and a discharge chamber) V1, V2, and V3, which are as many as the number of vanes 1351, 1352, and 1353, by the plurality of vanes 1351, 1352, and 1353. Each of the compression chambers V1, V2, and V3 changes in volume by the shape of the inner circumferential surface 1332 of the cylinder 133 and the eccentricity of the roller 134 while moving along the rotation of the roller 134. Refrigerant suctioned into the respective compression chambers V1, V2, and V3 is compressed while moving along the roller 134 and the vanes 1351, 1352, and 1353, and discharged into the inner space of the casing 110 through the respective discharge ports 1313 a, 1313 b, and 1313 c. This series of processes is repeated.

At this time, the refrigerant compressed in each compression chamber generates a gas reaction force and pushes the vane 1351, 1352, 1353 drawn out from the roller 134 toward the inside of the vane slot, but this gas reaction force is offset by centrifugal force generated by the rotation of the roller 134 and back pressure of the back pressure chamber 1344 a, 1344 b, 1344 c supporting the rear surface 1351 b, 1351 b, 1351 c of the vane 1351, 1352, 1353. Then, the front surface 1351 a, 1352 a, 1353 a of the vane 1351, 1352, 1353 is kept in contact with the inner circumferential surface 1332 of the cylinder 133, thereby suppressing or preventing leakage between the compression chambers V1, V2, and V3.

However, as described above, in the vane rotary compressor according to the embodiment, the front surfaces 1351 a, 1352 a, and 1353 a of the vanes 1351, 1352, 1353 may simultaneously receive compression pressure and suction pressure in a section from the reference point P between the cylinder 133 and the roller 134 and the suction port 1331. For this reason, each of the vanes 1351, 1352, and 1353 may tremble more in this section than in other sections due to pressure imbalance. The trembling of the vanes 1351, 1352, and 1353 may cause leakage between the compression chambers and hitting noise and vibration between the cylinder 1333 and each of the vanes 1351, 1352, and 1353. In addition, the inner circumferential surface 1332 of the cylinder 133 or the front surfaces 1351 a, 1352 a, and 1353 a of the vanes 1351, 1352, and 1353 may be worn, which may aggregate suction loss and compression loss.

Accordingly, in this embodiment, the pressure of the back pressure pocket 1315, 1325 for pressing the vane 135 toward the inner circumferential surface 1332 of the cylinder 133 may be formed in various ways so that the vane 135 is stably supported toward the cylinder 133. In particular, the back pressure pockets 1315 and 1325 in the vicinity of the reference point P may maintain discharge pressure or pressure higher than the discharge pressure, so as to prevent the vane 135 passing through the vicinity of the reference point P from being pushed due to insufficient back pressure, thereby effectively suppressing or preventing chattering of the vane 135.

FIG. 4 is an exploded perspective view of a sub bearing and a rotational shaft in FIG. 2 . FIG. 5 is an assembled planar view of FIG. 4 . FIG. 6 is a cross-sectional view, taken along the line “VI-VI” of FIG. 5 . FIG. 7 is a cross-sectional view taken along the line “X-X” of FIG. 5 , and FIG. 8 is a perspective view illustrating another embodiment of a communication groove of FIG. 2 .

Referring back to FIGS. 1 to 3 , the main back pressure pocket 1315 and the sub back pressure pocket 1325 may be formed in the main bearing 131 and the sub bearing 132, respectively. Each of the main back pressure pocket 1315 and the sub back pressure pocket 1325 may include a plurality of back pressure pockets [1315 a, 1315 b, and 1315 c], [1325 a, 1325 b, 1325 c] each having a different pressure in the circumferential direction.

For example, the number of each of the main back pressure pocket 1315 and the sub back pressure pocket 1325 may be three [1315 a, 1315 b, 1315 c], [1325 a, 1325 b, 1325 c]. These three back pressure pockets [1315 a, 1315 b, 1315 c], [1325 a, 1325 b, 1325 c] may form a first intermediate pressure, a second intermediate pressure (or first discharge pressure), and a super discharge pressure (or second discharge pressure), respectively.

Although not illustrated, each of the main back pressure pocket 1315 and the sub back pressure pocket 1325 may be more than three in number. However, even in this case, each of the back pressure pockets may be formed to have a different pressure along the rotational direction of the roller 134, for example, a gradually higher pressure along the rotational direction of the roller 134 based on the reference point P.

As described above, as the main back pressure pocket 1315 and the sub back pressure pocket 1325 are formed to correspond to each other based on the roller 134 except for a back pressure passage portion 138, which will be described hereinafter, the sub back pressure pocket 1325 will be mainly described, and repetitive description of the main back pressure pocket 1315 has been omitted.

Referring to FIGS. 4 and 5 , the sub back pressure pocket 1325 may include first sub back pressure pocket 1325 a, second sub back pressure pocket 1325 b, and a third sub back pressure pocket 1325 c. The first sub back pressure pocket 1325 a, the second sub back pressure pocket 1325 b, and the third sub back pressure pocket 1325 c may be sequentially disposed, based on the reference point P as a starting point, at preset or predetermined distances in the rotational direction of the roller 134.

For example, in the compression space V, the first sub back pressure pocket 1325 a may be formed in a region forming a pressure between the suction pressure and the intermediate pressure, the second sub back pressure pocket 1325 b in a region forming a pressure between the intermediate pressure and the discharge pressure, and the third sub back pressure pocket 1325 c in a region forming the discharge pressure or the super discharge pressure, respectively. Accordingly, the first sub back pressure pocket 1325 a forms the first intermediate pressure, the second sub back pressure pocket 1325 b forms the second intermediate pressure (or first discharge pressure) higher than the first intermediate pressure, and the third sub back pressure pocket 1325 c forms the super discharge pressure (or second discharge pressure) higher than the second intermediate pressure.

The first sub back pressure pocket 1325 a may be structurally formed as an almost closed space. For example, an inner circumferential side of the first sub back pressure pocket 1325 a may be blocked by the first sub bearing protrusion 1326 a to be almost isolated from the inner space 110 a of the casing 110. Accordingly, pressure of oil flowing into the first sub back pressure pocket 1325 a over the first sub bearing protrusion 1326 a may be lowered to the first intermediate pressure.

In addition, as an outer circumferential side of the first sub back pressure pocket 1325 a is disposed in a relatively low suction pressure and first intermediate pressure region, the oil in the first sub back pressure pocket 1325 a may leak into the compression space V through a gap between the sub bearing 132 and the roller 134. Accordingly, the first sub back pressure pocket 1325 a has a widest pocket volume while its pocket pressure (back pressure) is lower that the first intermediate pressure. Hereinafter, the fact that a back pressure pocket forms a closed space does not mean a completely sealed closed space, and a case in which a passage communicating with the back pressure pocket is not specifically provided will be described as a closed space for convenience. Therefore, a case in which a communication passage communicating with a back pressure pocket such as the second sub back pressure pocket 1325 b described hereinafter is specifically provided will be described as an open space for convenience.

The second sub back pressure pocket 1325 b may be formed as an open space. For example, an inner circumferential side of the second sub back pressure pocket 1325 b has a second sub bearing protrusion 1326 b with a low height or a communication passage (no reference numeral given), so that the rotational shaft 123 is open to the inner space 110 a of the casing 110 through the oil supply passage 125. Accordingly, the second sub back pressure pocket 1325 b defines an open space while forming the second intermediate pressure (or first discharge pressure) higher than the first intermediate pressure.

The third sub back pressure pocket 1325 c may be formed as a semi-closed space. For example, an inner circumferential side of the third sub back pressure pocket 1325 c may be blocked by a third sub bearing protrusion 1326 c to be closed from the inner space 110 a of the casing 110. However, as the third sub back pressure pocket 1325 c, as described above, communicates directly with the oil supply passage 125 of the rotational shaft 123 through the back pressure passage portion 138 described hereinafter, it does not structurally define a completely closed space with respect to the inner space 110 a of the casing 110.

However, as the third sub back pressure pocket 1325 c is formed in a discharge pressure region and the back pressure passage portion has a small inner diameter even if the inner circumferential side is blocked by the third sub bearing protrusion 1326 c, the third sub back pressure pocket 1325 c may be understood as a substantially closed space. Accordingly, the third sub back pressure pocket 1325 c defines a semi-closed space while forming the super discharge pressure (second discharge pressure) higher than the second intermediate pressure (or first discharge pressure).

Referring to FIGS. 4 to 7 , a volume of the third sub back pressure pocket 1325 c according to the embodiment may be smaller than a volume of the first sub back pressure pocket 1325 a as well as a volume of the second sub back pressure pocket 1325 b. Accordingly, it may be advantageous in that internal pressure of the third sub back pressure pocket 1325 c is formed to be higher than internal pressure of the second sub back pressure pocket 1325 b.

The first sub back pressure pocket 1325 a may have a longest arcuate length L1 and the third sub back pressure pocket 1325 c may have a shortest arcuate length L3. In other words, the arcuate length L3 of the third sub back pressure pocket 1325 c may be shorter than the arc length L1 of the first sub back pressure pocket 1325 a, and shorter than or equal to an arcuate length L2 of the second sub back pressure pocket 1325 b. This may suppress or prevent an excessive increase in section in which the vane 135 receives back pressure of the super discharge pressure. Accordingly, chattering between the vane 135 and the cylinder 133, which occurs in the vicinity of the reference point P, may be suppressed or prevented while an increase in friction loss in the section may effectively be prevented.

For example, if the reference point P is 0°, the first sub back pressure pocket 1325 a may have a section from approximately 0° to 150°, the second sub back pressure pocket 1325 b may have a section from approximately 160° to 260°, and the third sub back pressure pocket 1325 c may have a section from approximately 270° to 350°. Then, even in the case where the vane 135 or the vane slot 1343 is inclined by a preset or predetermined angle with respect to the radial direction passing through the center of rotation Or of the roller 134 as in the embodiment, the back pressure chamber 1344 to which the vane 135 belongs communicates with the third sub back pressure pocket 1325 c while the corresponding vane 135 passes through the reference point P. Accordingly, the rear surface 1351 b, 1352 b, 1353 b of the corresponding vane 135 receives the pressure of the third sub back pressure pocket 1325 c, that is, the back pressure corresponding to the super discharge pressure, and thus, the front surface 1351 a, 1352 a, 1353 a of the vane 135 overcomes the high discharge pressure in the vicinity of the reference point P so as to be brought into close contact with the inner circumferential surface 1332 of the cylinder 133.

Referring to FIGS. 6 and 7 , a radial width (hereafter, also referred to as a width) (no reference numeral given) of the third sub back pressure pocket 1325 c may be smaller than radial widths (no reference numeral given) of the other sub back pressure pocket 1325 a, 1325 b, and an axial depth (hereinafter, also referred to as a depth) H3 of the third sub back pressure pocket 1325 c may be smaller than axial depths H1 and H2 of the other sub back pressure pockets 1325 a and 1325 b. In addition, a length L3 and/or a width (no reference numeral given) and/or depth H3 of the third sub back pressure pocket 1325 c of the third sub back pressure pocket 1325 c may be smaller than lengths L1 and L2 and/or widths (no reference numeral given) and/or depths H1 and H2 of the other back pressure packets 1325 a and 1325 b. This embodiment illustrates an example in which the length L3, width (no reference numeral given), and depth H3 of the third sub back pressure pocket 1325 c is smaller than of the lengths L1 and L2, widths (no reference numeral given), and depths H1 and H2 of the other sub back pressure pockets 1325 a and 1325 b.

Accordingly, the volume of the third sub back pressure pocket 1325 c may be smaller than the volume of the first sub back pressure pocket 1325 a as well as the volume of the second sub back pressure pocket 1325 b. This may be advantageous in terms of maintaining the pressure of the third sub back pressure pocket 1325 c to be higher than the internal pressure of the first sub back pressure pocket 1325 a as well as the internal pressure of the second sub back pressure pocket 1325 b.

Although not illustrated, it is not always necessary that the length L3, width (no reference numeral given), and depth H3 of the third sub back pressure pocket 1325 c is smaller than of the lengths L1 and L2, widths (no reference numeral given), and depths H1 and H2 of the other sub back pressure pockets 1325 a and 1325 b. For example, the length L3, width (no reference numeral given) and depth H3 of the third sub back pressure pocket 1325 c may be equal to or slightly larger than at least the length L2, width (no reference numeral given), and depth H2 of the neighboring second sub back pressure pocket 1325 b.

Even in this case, the inner circumferential side of the second sub back pressure pocket 1325 b is open or has a communication passage (no reference numeral given) so as to define a so-called open space. On the other hand, the third sub back pressure pocket 1325 c communicates with the inner space 110 a of the casing 110 by the back pressure passage portion 138 to define a semi-closed space, but as illustrated in FIG. 5 , it defines a substantially closed space because the back pressure passage portion 138 has the small inner diameter and the vane 135 closes it during the reciprocating motion of the vane 135. Therefore, the pressure of the third sub back pressure pocket 1325 c may be higher than the pressure of the second sub back pressure pocket 1325 b.

Referring to FIGS. 4 to 7 , the third sub back pressure pocket 1325 c, as described above, communicates with the inner space 110 a of the casing 110 through the back pressure passage portion 138, precisely, the oil supply passage 125 which is an internal passage of the rotational shaft 123. Accordingly, some of oil suctioned up through the oil supply passage 125 of the rotational shaft 123 is directly introduced into the third sub back pressure pocket 1325 c through the back pressure passage portion 138.

The back pressure passage portion 138 may include a first back pressure hole 138 a, a second back pressure hole 138 b, and a communication groove 138 c. The first back pressure hole 138 a may be formed through the rotational shaft 123, and the second back pressure hole 138 b may be formed through the sub bearing 132. The first back pressure hole 138 a and the second back pressure hole 138 b may communicate with each other periodically or continuously through the communication groove 138 c. In this embodiment, an example in which the first back pressure hole 138 a and the second back pressure hole 138 b communicate periodically will be described first, and an example in which the first back pressure hole 138 a and the second back pressure hole 138 b communicate continuously will be described hereinafter.

Referring to FIGS. 4 and 5 , the first back pressure hole 138 a according to this embodiment penetrates from an inner circumferential surface of the oil supply passage 125 constituting the inner circumferential surface of the rotational shaft 123 to the outer circumferential surface of the rotational shaft 123, and it may also be understood as a third oil supply hole. In other words, the first oil supply hole 126 a, the second oil supply hole 126 b, and the first back pressure hole 138 a are disposed at preset or predetermined distances in the axial direction, as aforementioned. The first oil supply hole 126 a penetrates radially toward the main bearing hole 1312 a, and each of the second oil supply hole 126 b and the first back pressure hole 138 a penetrates radially toward the sub bearing hole 1322 a. The first back pressure hole 138 a communicates with the second back pressure hole 138 b at a position lower than the second oil supply hole 126 b.

The first back pressure hole 138 a may be provided as one in number or as a plurality in the circumferential direction. In this embodiment, an example including the single first back pressure hole 138 a is illustrated. However, embodiments may be equally applied to the case in which the plurality of first back pressure holes 138 a are disposed.

The first back pressure hole 138 a may be formed to be smaller than or equal to the first oil supply hole 126 a and/or the second oil supply hole 126 b. For example, an inner diameter D31 of the first back pressure hole 138 a may be smaller than an inner diameter D1 of the first oil supply hole 126 a and/or an inner diameter D2 of the second oil supply hole 126 b within a range in which pressure of oil passing through the back pressure passage portion 138 is not lowered. This may prevent oil suctioned through the oil supply passage 125 from flowing out excessively through the first back pressure hole 138 a before reaching the first oil supply hole 126 a or the second oil supply hole 126 b, thereby suppressing or preventing an occurrence of oil shortage in another back pressure pocket.

As illustrated in this embodiment, the inner diameter D31 of the first back pressure hole 138 a is smaller than the inner diameter D1 of the first oil supply hole 126 a and/or the inner diameter D2 of the second oil supply hole 126 b, and thus, the inner diameter D1 of the first oil supply hole 126 a or the inner diameter D2 of the second oil supply hole 126 b becomes larger than the inner diameter D3 of the back pressure passage portion 138. Accordingly, the oil suctioned through the oil supply passage 125 may be sufficiently supplied to the first and second main back pressure pockets 1315 a and 1315 b and the first and second sub back pressure pockets 1325 a and 1325 b through the first and second oil supply holes 126 a and 126 b. This may prevent in advance an occurrence of insufficient back pressure due to an oil shortage in the first or second main back pressure pocket 1315 a or 1315 b or the first or second sub back pressure pocket 1325 a or 1325 b. At the same time, an occurrence of friction loss due to an oil shortage on the main bearing surface 1312 b and/or the sub bearing surface 1322 b may be prevented in advance.

In addition, the first back pressure hole 138 a may be formed on a same circumference as the second oil supply hole 126 b, but may be formed at a height as different as possible from a height of the second oil supply hole 126 b. For example, the first back pressure hole 138 a may be located at a lower position than the second oil supply hole 126 b, that is, at a lower end of the rotational shaft 123. Accordingly, the first back pressure hole 138 a is located closer to the oil storage space 110 b of the casing 110 than the second oil supply hole 126 b.

Then, the oil suctioned through the oil supply passage 125 may be introduced into the first back pressure hole 138 a before reaching the second oil supply hole 126 b, to be supplied to the third main back pressure packet 1315 c and the third sub back pressure pocket 1325 c, other than the other back pressure pockets 1315 a, 1325 a, 1315 b, 1325 b. This may suppress or prevent the vane 135 from being spaced apart from the cylinder 133 in the vicinity of the reference point P at the initial startup of the compressor, thereby preventing an initial startup failure. Accordingly, when the compressor is applied to an air conditioning apparatus, a delay of an air conditioning effect may be prevented.

At the same time, when the first back pressure hole 138 a and the second oil supply hole 126 b are formed on the same circumference, the rigidity of the rotational shaft 123 may decrease. However, as the first back pressure hole 138 a and the second oil supply hole 126 b are spaced apart in the axial direction, the decrease in rigidity of the rotational shaft may be suppressed or prevented and reliability may be enhanced.

Referring to FIGS. 4 to 7 , the second back pressure hole 138 b according to the embodiment may be formed through between the third sub back pressure pocket 1325 c and the inner circumferential surface of the sub bearing 132. For example, one (first) end of the second back pressure hole 138 b is open to a bottom surface of the third sub back pressure pocket 1325 c, and another (second) end of the second back pressure hole 138 b is open to the sub bearing surface 1322 b defining the inner circumferential surface of the sub bearing hole 1322 a. Accordingly, the third sub back pressure pocket 1325 c may communicate with the first back pressure hole 138 a through the second back pressure hole 138 b.

The second back pressure hole 138 b may be smaller than or equal to the first back pressure hole 138 a. For example, an inner diameter D32 of the second back pressure hole 138 b may be the same as an inner diameter D31 of the first back pressure hole 138 a. In other words, the inner diameter D32 of the second back pressure hole 138 b may be smaller than the inner diameter D1 of the first oil supply hole 126 a and/or the inner diameter D2 of the second oil supply hole 126 b. Accordingly, oil introduced into the third sub back pressure pocket 1325 c may be prevented from easily flowing out through the second back pressure hole 138 b and the first oil supply hole 138 a when the vane 135 moves backward, which may result in sufficiently maintaining the back pressure of the third sub back pressure pocket 1325 c.

Although not illustrated, the inner diameter D32 of the second back pressure hole 138 b may be larger than the inner diameter D31 of the first back pressure hole 138 a. In other words, the inner diameter D31 of the first back pressure hole 138 a may be larger than the inner diameter D32 of the second back pressure hole 138 b and smaller than the inner diameters D1 and D2 of the first and second oil supply holes 126 a and 126 b.

In this case, a part or portion of the oil suctioned through the oil supply passage 125 flows between the inner circumferential surface of the sub bearing 132 and the outer circumferential surface of the rotational shaft 123 through the first back pressure hole 138 a. The part of the oil is then partially guided to the third sub back pressure pocket 1325 c through the second back pressure hole 138 b and the remaining part or portion of the oil lubricates between the inner circumferential surface of the sub bearing 132 and the outer circumferential surface of the rotational shaft 123. Accordingly, oil may be sufficiently supplied even to the third sub back pressure pocket 1325 c, while effectively lubricating even the sub bearing surface 1322 b between the inner circumferential surface of the sub bearing 132 and the outer circumferential surface of the rotational shaft 123.

In addition, the second back pressure hole 138 b may be formed through a center of the third sub back pressure pocket 1325 c or may be formed through the same at an eccentric position. In this embodiment, an example in which the second back pressure hole 138 b is formed through the sub bearing surface 1322 b at a position eccentric to a side from the center of the third sub back pressure pocket 1325 c, precisely, toward the reference point P is illustrated.

In other words, the second oil supply hole may be formed at a position where it intermittently overlaps the vane 135 during the reciprocating motion of the vane 135, and the inner diameter D32 of the second oil supply hole 138 b may be smaller than a width t of the vane 135. Accordingly, as illustrated in FIGS. 3 and 5 , the vane 135 passing through the third sub back pressure pocket 1325 c may block the second back pressure hole 138 b at a position where it receives a high gas repulsive force from the compression space V, in other words, a position close to the third discharge port 1313 c. With this configuration, the third sub back pressure pocket 1325 c may define a closed space at a position where the vane 135 is closest to the third discharge port 1313 c, so as to form a high back pressure. If the second back pressure hole 138 b is formed in the center of the third sub back pressure pocket 1325 c or opposite to that illustrated in the embodiment, the second back pressure hole 138 b may be open at the position where the vane 135 is closest to the third discharge port 1313 c and the third sub back pressure pocket 1325 c may not define the closed space. Then, the back pressure of the third sub back pressure pocket 1325 c may be lowered at a position where the vane 135 is close to the third discharge port 1313 c, and thus, the vane 135 may not be effectively supported.

Also, the second back pressure hole 138 b may be inclined obliquely. Accordingly, oil passing through the first back pressure hole 138 a may smoothly flow into the third sub back pressure pocket 1325 c without interruption.

Although not illustrated, the second back pressure hole 138 b may be bent. For example, the second back pressure hole 138 b may include a first through hole portion extending axially from the third sub back pressure pocket 1325 c, and a second through hole portion (not illustrated) formed through the inner circumferential surface of the sub bearing hole 1322 a from the outer circumferential surface of the sub bearing 132 via the first through hole portion. In this case, the back pressure passage portion 138 serves as a kind of oil storage space. Accordingly, a predetermined amount of oil may be stored in the back pressure passage portion 138 even when the compressor is stopped, and then may be quickly supplied to the third sub back pressure pocket 1325 c when the compressor is restarted or may lubricate the sub bearing surface 1322 b.

The communication groove 138 c according to the embodiment is formed between the first back pressure hole 138 a and the second back pressure hole 138 b. Accordingly, the first back pressure hole 138 a and the second back pressure hole 138 b may communicate with each other through the communication groove 138 c.

The communication groove 138 c may be formed in at least one of an outer end of the first back pressure hole 138 a or an inner end of the second back pressure hole 138 b facing the same. In other words, the communication groove 1413 may be formed in at least one of the outer circumferential surface of the rotational shaft 123 or the sub bearing surface 1322 b defining the inner circumferential surface of the sub bearing 132 facing the outer circumferential surface of the rotational shaft 123. This embodiment illustrates an example in which the communication groove 138 c is formed in the inner end of the second back pressure hole 138 b, that is, in the sub bearing surface 1322 b. However, the communication groove 138 c may alternatively be formed in the outer circumferential surface of the rotational shaft 123 or may be formed in each of the outer circumferential surface of the rotational shaft 123 and the sub bearing surface 1322 b.

However, when the communication groove 138 c is formed in the sub bearing 132, as described above, it may be recessed by a preset or predetermined depth into the sub bearing surface 1322 b. However, a bearing (not illustrated) configured as a bush bearing may be inserted into the sub bearing surface 1322 b. In this case, the communication groove 138 c may be formed directly in the sub bearing surface 1322 b, or may be formed as a communication groove through a bearing (not illustrated) inserted into the sub bearing surface 1322 b. Hereinafter, it will be described that the communication groove 138 c is formed in the sub bearing surface 1322 b for convenience. Also, an example in which a second communication groove 1382 c is formed in the main bearing surface 1312 b will be described hereinafter in another embodiment.

Referring to FIG. 4 , the communication groove 138 c may be formed in an arcuate shape lengthwise in the circumferential direction. In this case, the communication groove 138 c may be formed to have a same width and depth in the circumferential direction, and its center may be deep and both ends shallow. In other words, when the communication groove 138 c is formed to be recessed into the sub bearing surface 1322 b, as described above, the width or depth of the communication groove 138 c may be large at a center and small at both ends. However, when the communication groove 138 c is formed through a bearing (not illustrated) inserted into the sub bearing surface 1322 b, it may be understood that the communication groove 138 c is formed to have the same width and depth in the circumferential direction.

However, as this embodiment illustrates the example in which the communication groove 138 c is formed in the sub bearing surface 1322 b, it will be understood that the communication groove 138 c is formed so that the width and depth at the center are larger than the width and depth at both ends. In this case, the communication groove 138 c may be easily processed into an arcuate shape and oil may be more smoothly guided to the second back pressure hole 138 b.

When the communication groove 138 c is formed in the arcuate shape, an arcuate length of the communication groove 138 c may be longer than the inner diameter D31 of the first back pressure hole 138 a, and communicates with the first back pressure hole 138 a periodically. For example, the arc length of the communication groove 138 c may be formed so that an arcuate angle formed by being connected to the first back pressure hole 138 a is smaller than at least 360°, that is, smaller than 180°. Accordingly, the communication groove 138 c may communicate with the first back pressure hole 138 a periodically, not continuously. Accordingly, during operation of the compressor, the back pressure passage portion 138 is periodically blocked in a section (rotational angle) in which the communication groove 138 c does not communicate with the first back pressure hole 138 a. Then, the third sub back pressure pocket 1325 c may become a closed space and thus oil leakage from the third sub back pressure pocket 1325 c may be minimized such that the third sub back pressure pocket 1325 c may maintain the high back pressure. This may result in more stably supporting the vane.

However, the communication groove 138 c may alternatively be formed in a circular shape. The communication groove 138 c may be formed to have the same depth along the circumferential direction. Accordingly, the first back pressure hole 138 a and the second back pressure hole 138 b may continuously communicate with each other through the communication groove 138 c even when the rotational shaft 123 rotates.

However, when the communication groove 138 c is formed in the circular shape, it may be advantageous in terms of processing that the communication groove 138 c is formed in the outer circumferential surface of the rotational shaft 123 rather than the inner circumferential surface of the sub bearing 132. In other words, as a bearing (not illustrated) configured as a bush bearing is inserted into the sub bearing surface 1322 b, it is difficult to form the communication groove in the circular shape in the inner circumferential surface of the sub bearing 132, that is, the sub bearing surface 1322 b. Accordingly, as illustrated in FIG. 8 , the communication groove 138 c may extend into the circular shape from the outer circumferential surface of the rotational shaft 123 in the circumferential direction.

As described above, when the communication groove 138 c is formed in the circular shape to continuously communicate with the first back pressure hole 138 a, oil passing through the first back pressure hole 138 a may continuously be supplied into the second back pressure hole 138 b through the communication groove 138 c and then continuously supplied into the third sub back pressure pocket 1325 c without interruption. This may prevent in advance a decrease in back pressure due to an oil shortage in the third sub back pressure pocket 1325 c, more precisely, in the corresponding back pressure chamber 1344.

As described above, the main bearing 131 may further include the third main back pressure pocket 1315 c in addition to the first main back pressure pocket 1315 a and the second main back pressure pocket 1315 b. The first main back pressure pocket 1315 a, the second main back pressure pocket 1315 b, and the third main back pressure pocket 1315 c may be formed symmetrically with the first sub back pressure pocket 1325 a, the second sub back pressure pocket 1325 b, and the third sub back pressure pocket 1325 b. However, unlike the third sub back pressure pocket 1325 c, the third main back pressure pocket 1315 c may not separately include the back pressure passage portion 138 that communicates directly with the oil supply passage 125, and oil introduced into the third sub back pressure pocket 1325 c may move to the third main back pressure pocket 1315 c through the back pressure chamber 1344.

The first main back pressure pocket 1315 a, the second main back pressure pocket 1315 b, and the third main back pressure pocket 1315 c may communicate with the first sub back pressure pocket 1325 a, the second sub back pressure pocket 1325 b, and the third sub back pressure pocket 1325 b, respectively, through the corresponding back pressure chambers 1344 passing through the back pressure pockets. Accordingly, each vane 135 is pressed toward the cylinder 133 by the back pressure of each back pressure chamber 1344, which is defined as the same pressure as the pressure of each back pressure pocket 1315 and 1325, and the front surface 1351 a, 1352 a, 1353 a of the vane 135 is slidably brought into contact with the inner circumferential surface 1332 of the cylinder 133.

Hereinafter, description will be given of operating effects of the back pressure passage portion in the vane rotary compressor according to the embodiment. FIG. 9 is a cross-sectional view illustrating a process of supplying oil to a back pressure pocket in a rotary compressor in accordance with an embodiment.

Referring to FIG. 9 , in the vane rotary compressor according to the embodiment, the plurality of back pressure pockets 1315 and 1325 having different back pressures may be formed in the main bearing 131 and/or the sub bearing 132 in the rotational direction of the roller 134, and the third main back pressure pocket 1315 c and the third sub back pressure pocket 1325 c which are closest to the third discharge port 1313 c may form a higher pressure than the other back pressure pockets 1315 and 1325. In other words, as the third sub back pressure pocket 1325 c is directly connected to the oil supply passage 125 of the rotational shaft 123 through the back pressure passage portion 138, a part or portion of oil suctioned along the oil supply passage 125 is introduced directly into the third sub back pressure pocket 1325 c through the back pressure passage portion 138. Accordingly, oil in the third sub back pressure pocket 1325 c and the third main back pressure pocket 1315 c communicating therewith forms the super discharge pressure (second discharge pressure) higher than the discharge pressure (first discharge pressure) due to an increase in pressure by centrifugal force and an increase in pressure in a closed space.

Then, the rear surface 1351 b, 1352 b, 1353 b of the vane 135 passing through the reference point P receives the high back pressure of the super discharge pressure (second discharge pressure), which is transmitted from the corresponding back pressure chamber 1344 through the third main back pressure pocket 1315 c and/or the third sub back pressure pocket 1325 c. The vane 135 passing the reference point P receives the high back pressure due to the third main back pressure pocket 1315 c and the third sub back pressure pocket 1325 c to be pressed toward the inner circumferential surface 1332 of the cylinder 133. Accordingly, the front surface 1351 a, 1352 a, 1353 a of each vane 135 passing through the reference point P may be brought into close contact with the inner circumferential surface 1332 of the cylinder 133, thereby preventing chattering of the vane 135. This may suppress or prevent wear of the inner circumferential surface 1332 of the cylinder 133 or the front surface 1351 a, 1352 a, 1353 a of the vane 135 in the vicinity of the reference point P, and simultaneously preventing leakage between compression chambers while reducing vibration noise in the vicinity of the reference point P, thereby improving compression efficiency.

In addition, the chattering of the vane 135 may be more severe at the initial startup of the compressor. However, oil is quickly supplied to the third sub back pressure pocket 1325 c in the vicinity of the reference point P through the back pressure passage portion 138, which communicates with the lower end portion of the oil supply passage 125. Accordingly, the vane may be brought into close contact with the cylinder near the reference point P even at the initial startup of the compressor. This may prevent an initial startup failure and enhance compression efficiency. Therefore, an air conditioning effect may be quickly exhibited when the compressor is applied to an air conditioning apparatus, thereby enhancing reliability.

This may also be confirmed through the graph shown in FIG. 10 . FIG. 10 is a graph showing comparison results of a vane contact force for each rotational angle of a vane rotary compressor according to an embodiment with that of the related art.

As shown in FIG. 10 , the vane contact force [N] exceeds a reference value of zero (0) until a rotational angle of the rotational shaft 123 is approximately 240°, and thus, the state in which the front surface 1351 a, 1352 a, 1353 a of the vane 135 is almost brought into contact with the inner circumferential surface 1332 of the cylinder 133 may be maintained. However, the vane contact force [N] may be abruptly lowered from after the rotational angle of the rotational shaft 123 exceeds approximately 240°. This is because, as described above, pressure in the compression chamber V3 near the reference point P increases significantly.

In the related art (indicated by a dashed-dotted line), the main back pressure pocket 1315 and the sub back pressure pocket 1325 form the discharge pressure (first discharge pressure) or the second intermediate pressure lower than the discharge pressure even at a position closest to the reference point P, and thus, the vane contact force [N] is lower than the reference value (0). For this reason, in the related art, the front surface 1351 a, 1352 a, 1353 a of the vane 135 is spaced apart from the inner circumferential surface 1332 of the cylinder 133 in the vicinity of the reference point P, which may cause chattering of the vane 135 and leakage between the compression chambers.

However, in this embodiment (indicated by a solid line), as described above, the main back pressure pocket 1315 and the sub back pressure pocket 1325 forming the super discharge pressure (second discharge pressure) are located at the position closest to the third discharge port 1313 c. Accordingly, the vane contact force [N] greater than the reference value (0) is maintained even after the rotational angle of the rotational shaft 123 passes approximately 240°. Therefore, in this embodiment, the front surface 1351 a, 1352 a, 1353 a of the vane 135 may be kept brought into contact with the inner circumferential surface 1332 of the cylinder 133 in the vicinity of the reference point P, which may prevent the chattering of the vane 135 and the leakage between the compression chambers.

Those effects described above may be more expected in the rotary compressor according to the embodiment when a high-pressure refrigerant, such as R32, R410a, or CO₂, is used.

Hereinafter, description will be given of another embodiment of a back pressure passage portion. That is, in the previous embodiment, the back pressure passage portion is formed continuously through the sub bearing and the rotational shaft, but in some cases, may be formed merely through the sub bearing.

FIG. 11 is a perspective view illustrating another embodiment of a back pressure passage unit of FIG. 2 . FIG. 12 is an assembled cross-sectional view of FIG. 11 .

Referring to FIGS. 11 and 12 , the basic configuration and operating effects of the vane rotary compressor according to this embodiment are almost the same as those of the previous embodiment, and thus, repetitive description has been omitted. For example, the basic configuration of the main bearing 131, the sub bearing 132, the cylinder 133, the roller 134, and the vane 135 constituting the compression part in the vane rotary compressor according to this embodiment is substantially the same as those of the previous embodiment.

In addition, the first sub back pressure pocket 1325 a, the second sub back pressure pocket 1325 b, and the third sub back pressure pocket 1325 c are sequentially disposed in a sub sliding surface 1321 a of the sub bearing 132, based on the reference point P as a starting point in the rotational direction of the roller 134. The first sub back pressure pocket 1325 a is formed from a suction pressure region to an intermediate pressure region, the second sub back pressure pocket 1325 b is formed from the intermediate pressure region to a discharge pressure region. Also, the third sub back pressure pocket 1325 c is connected to the back pressure passage portion 138 so as to directly communicate with the inner space 110 a of the casing 110 forming the discharge pressure, and is formed in the discharge pressure region. Accordingly, the first sub back pressure pocket 1325 a forms the first intermediate pressure, the second sub back pressure pocket 1325 b forms the second intermediate pressure (or first discharge pressure) higher than the first intermediate pressure, and the third sub back pressure pocket 1325 c forms the super discharge pressure (or second discharge pressure) higher than the second intermediate pressure.

However, the back pressure passage portion 138 according to the embodiment may be formed through the sub bearing 132 so that the third sub back pressure pocket 1325 c is directly connected to the inner space 110 a of the casing 110. For example, the back pressure passage portion 138 may include only one through hole. An upper end of the back pressure passage portion 138 may be formed through the bottom surface of the third sub back pressure pocket 1325 c to communicate with the third sub back pressure pocket 1325 c, and a lower end of the back pressure passage portion 138 may be formed through up to a lower end of the sub bearing 132, that is, a lower surface of the sub plate portion 1321 defining an opposite surface of the sub sliding surface 1321 a, so as to be immersed in the oil storage space 110 b of the casing 110.

The back pressure passage portion 138 may be formed eccentrically from the center of the third sub back pressure pocket 1325 c toward the reference point P. The operating effects according to this embodiment are the same as those in the previous embodiment.

An inner diameter D33 of the back pressure passage portion 138, as in the previous embodiment, may be smaller than the inner diameter D1 of the first oil supply hole 126 a and the inner diameter D2 of the second oil supply hole 126 b. The operating effects according to this embodiment are almost similar to those in the previous embodiment. However, in the previous embodiment, the back pressure passage portion 138 communicates with the oil supply passage 125 of the rotational shaft 123 such that oil is pumped using centrifugal force generated when the rotational shaft 123 rotates, whereas this embodiment illustrates that oil is supplied using pressure of the inner space 110 a of the casing 110. Accordingly, it may be advantageous in terms of oil supply that the inner diameter D33 of the back pressure passage portion 138 is slightly larger than the inner diameters D31 and D32 of the back pressure passage portion 138 in the embodiment of FIG. 4 .

However, even in this case, when the inner diameter D33 of the back pressure passage portion 138 is excessively large, for example, larger than or equal to the inner diameter D1 of the first oil supply hole 126 a and the inner diameter D2 of the second oil supply hole 126 b, oil in the third sub back pressure pocket 1325 c may flow into the back pressure passage portion 138 when the vane moves backward, which may be disadvantageous in forming sufficient second discharge pressure. Therefore, the inner diameter D33 of the back pressure passage portion 138 may be smaller than the inner diameter D1 of the first oil supply hole 126 a and/or the inner diameter D2 of the second oil supply hole 126 b.

As described above, when the back pressure passage portion 138 is formed through the sub bearing 132, the back pressure passage portion 138 may be easily processed, thereby reducing manufacturing costs. In this case, not only the length of the back pressure passage portion 138 may be shortened but also the back pressure passage portion 138 may be maintained in an open state, so that oil may be quickly supplied to the third sub back pressure pocket 1325 c at the initial startup of the compressor. This may more effectively suppress the initial startup failure.

Hereinafter, description will be given of still another embodiment of a back pressure passage portion. That is, the back pressure passage portion is formed through only the sub bearing in the previous embodiments, but in some cases, may be formed through each of the sub bearing and the main bearing.

FIG. 13 is an exploded perspective view illustrating still another embodiment of a back pressure passage unit. FIG. 14 is an assembled cross-sectional view of FIG. 13 .

Referring to FIGS. 13 and 14 , the basic configuration and operating effects of the vane rotary compressor according to this embodiment are almost the same as those of the previous embodiment, and thus, repetitive description has been mitted. For example, the basic configuration of the main bearing 131, the sub bearing 132, the cylinder 133, the roller 134, and the vane 135 constituting the compression part in the vane rotary compressor according to this embodiment is substantially the same as those of the previous embodiment.

In addition, the first sub back pressure pocket 1325 a, the second sub back pressure pocket 1325 b, and the third sub back pressure pocket 1325 c are sequentially disposed in the sub sliding surface 1321 a of the sub bearing 132 based on the reference point P as a starting point in the rotational direction of the roller 134. Also, the first main back pressure pocket 1315 a, the second main back pressure pocket 1315 b, and the third main back pressure pocket 1315 c are sequentially disposed in the main sliding surface 1312 a of the main bearing 131 based on the reference point P as a starting point in the rotational direction of the roller 134.

However, in this embodiment, the third sub back pressure pocket 1325 c and the oil supply passage 125 of the rotational shaft 123 may communicate with each other through a first back pressure passage portion 1381, and the third main back pressure pocket 1315 c and the oil supply passage 125 of the rotational shaft 123 may communicate with each other through a second back pressure passage portion 1382. Accordingly, a part or portion of oil suctioned through the oil supply passage 125 may be supplied to the third sub back pressure pocket 1325 c through the first back pressure passage portion 1381, and to the third main back pressure pocket 1315 c through the second back pressure passage portion 1382. Therefore, the back pressure of the third sub back pressure pocket 1325 c and the third main back pressure pocket 1315 c may be raised to the super discharge pressure (or second discharge pressure), which may result in more effectively supporting the rear surface of the vane 135 passing through the reference point P.

More specifically, the first back pressure passage portion 1381 may include first back pressure hole 1381 a, second back pressure hole 1381 b, and first communication groove 1381 c. The first back pressure hole 1381 a is the same as the first back pressure hole 138 a of the embodiment of FIG. 4 , the second back pressure hole 1381 b is the same as the second back pressure hole 138 b of the embodiment of FIG. 4 , and the first communication groove 1381 c is the same as the communication groove 138 c of the embodiment of FIG. 4 . Therefore, repetitive description of the specific configuration and operating effects of the first back pressure hole 1381 a, the second back pressure hole 1381 b, and the first communication groove 1381 c has been omitted.

The second back pressure passage portion 1382 may include a third back pressure hole 1382 a, a fourth back pressure hole 1382 b, and a second communication groove 1382 c. The third back pressure hole 1382 a, similar to the first back pressure hole 1381 a, may be formed through from the inner circumferential surface of the rotational shaft 123 defining the inner circumferential surface of the oil supply passage 125 to the outer circumferential surface of the rotational shaft 123. The fourth back pressure through hole 1382 b, similar to the second back pressure hole 1381 b, may be formed through between the third main back pressure pocket 1315 c and the main bearing hole 1312 a of the main bearing 131. Also, the second communication groove 1382 c, similar to the first communication groove 1381 c, may be recessed into an arcuate or circular shape into the inner circumferential surface of the main bearing hole 1312 a and/or the outer circumferential surface of the rotational shaft 123.

The third back pressure hole 1382 a is substantially the same as the first back pressure hole 1381 a, the fourth back pressure hole 1382 b is substantially the same as the first back pressure hole 1381 a, and the second communication groove 1382 c is the same as the first communication groove 1381 c. Therefore, repetitive description of the third back pressure hole 1382 a, the fourth back pressure hole 1382 b, and the second communication groove 1382 c of the second back pressure passage portion 1382 has been omitted.

As described above, when the first back pressure passage portion 1381 and the second back pressure passage portion 1382 are respectively formed, oil is directly supplied from the oil supply passage 125 of the rotational shaft 123 to the third sub back pressure pocket 1325 c and the third main back pressure pocket 1315 c through the first back pressure passage portion 1381 and the second back pressure passage portion 1382. Accordingly, the pressure of the third sub back pressure pocket 1325 c and the pressure of the third main back pressure pocket 1315 c are maintained almost uniformly, so that back pressure in the corresponding back pressure chamber 1344 between the third sub back pressure pocket 1325 c and the third main back pressure pocket 1315 c may be uniformly distributed in the axial direction. Thus, the back pressure for the corresponding vane 135 passing through between the third sub back pressure pocket 1325 c and the third main back pressure pocket 1315 c may be uniformly distributed along the axial direction, thereby more effectively reducing chattering and/or uneven wear between the vane 135 and the cylinder 133.

This may be particularly advantageous in a vertical rotary compressor. That is, in the vertical rotary compressor, oil is dropped due to its own weight, so an amount of oil in the third main back pressure pocket 1315 c is relatively smaller than an amount of oil in the third sub back pressure pocket 1325 c. Due to this, back pressure with respect to the rear side of the vane 135 is unevenly distributed along the axial direction in the vicinity of the reference point P, and this may increase chattering and/or uneven wear of the vane 135 and the cylinder 133. However, as in the embodiment, when the first back pressure passage portion 1381 is connected to the third sub back pressure pocket 1325 c and the second back pressure passage portion 1382 is connected to the third main back pressure pocket 1315 c, respectively, the back pressure with respect to the vane 135 may be distributed almost uniformly along the axial direction. This may reduce chattering between the vane 135 and the cylinder 133 and friction loss due to the chattering in the vicinity of the reference point P in the vertical rotary compressor, thereby enhancing compression efficiency.

Although not illustrated, the first back pressure passage portion 1381 may not communicate with the oil supply passage 125 of the rotational shaft 123 but directly communicate with the inner space 110 a of the casing 110 through the sub bearing 132 as in the embodiment of FIG. 11 . This will be replaced with the description of the embodiment of FIG. 11 .

Hereinafter, description will be given of another embodiment of a sub bearing. That is, in the previous embodiments, the main back pressure pocket and the sub back pressure packet are formed in the main sliding surface and the sub sliding surface, respectively, but in some cases, a lubricating portion in addition to the main back pressure pocket or the sub back pressure pocket may further be formed on at least one of the main sliding surface or the sub sliding surface. Hereinafter, an example in which a first lubricating portion and a second lubricating portion are respectively formed on the main sliding surface and the sub sliding surface will be mainly described.

FIG. 15 is an exploded perspective view illustrating another embodiment of the compression part in FIG. 1 . FIG. 16 is a planar view illustrating a main bearing in FIG. 15 . FIG. 17 is a planar view illustrating a sub bearing in FIG. 15 , and FIG. 18 is an assembled cross-sectional view of FIG. 15 .

Referring to FIGS. 15 to 18 , the basic configuration and operating effects of the vane rotary compressor according to this embodiment are almost the same as those of the previous embodiment, and thus, repetitive description thereof has been omitted. For example, the basic configuration of the main bearing 131, the sub bearing 132, the cylinder 133, the roller 134, and the vane 135 constituting the compression part in the vane rotary compressor according to this embodiment is substantially the same as those of the previous embodiment.

In addition, the first sub back pressure pocket 1325 a, the second sub back pressure pocket 1325 b, and the third sub back pressure pocket 1325 c are sequentially disposed in sub sliding surface 1321 a of the sub bearing 132, based on the reference point P as a starting point in the rotational direction of the roller 134. The first sub back pressure pocket 1325 a is formed from a suction pressure region to an intermediate pressure region, the second sub back pressure pocket 1325 b is formed from the intermediate pressure region to a discharge pressure region, and the third sub back pressure pocket 1325 c is formed in the discharge pressure region. Accordingly, the first sub back pressure pocket 1325 a forms a first intermediate pressure, the second sub back pressure pocket 1325 b forms a second intermediate pressure (or first discharge pressure), and the third sub back pressure pocket 1325 c forms a super discharge pressure (or second discharge pressure).

In addition, the third sub back pressure pocket 1325 c may communicate with the oil supply passage 125 of the rotational shaft 123 through the first back pressure passage portion 1381, and the third main back pressure pocket 1315 c may communicate with the oil supply passage 125 of the rotational shaft 123 through the second back pressure passage portion 1382. As the first back pressure passage portion 1381 and the second back pressure passage portion 1382 are the same as those in the previous embodiment of FIG. 13 , repetitive description thereof has been omitted.

However, in this embodiment, a first lubricating portion 1391 may be formed on the sub sliding surface 1321 a of the sub bearing 132 and a second lubricating portion 1392 may be formed on the main sliding surface 1312 a of the main bearing 131, respectively. The first lubricating portion 1391 and the second lubricating portion 1392 may be formed at positions corresponding to each other in the axial direction with the roller 134 or the vane 135 interposed therebetween.

The first lubricating portion 1391 may include a first lubrication pocket 1391 a and a first lubrication passage 1391 b. The first lubrication pocket 1391 a is a portion substantially defining a space of the first lubricating portion 1391, and the first lubrication passage 1391 b is a portion for guiding oil to the first lubrication pocket 1391 a.

The first lubrication pocket 1391 a may be formed to surround the second sub back pressure pocket 1325 b and the third sub back pressure pocket 1325 c radially with a preset or predetermined distance at an outer circumferential side of the second sub back pressure pocket 1325 b and the third sub back pressure pocket 1325 c. Accordingly, the first lubrication pocket 1391 a may radially overlap the second sub back pressure pocket 1325 b and the third sub back pressure pocket 1325 c.

More specifically, the first lubrication pocket 1391 a may be formed in an arcuate shape. An arcuate length L4 of the first lubrication pocket 1391 a may be longer than or equal to a length that is the sum of an arcuate length L2 of the second sub back pressure pocket 1325 b and an arcuate length L3 of the third sub back pressure pocket 1325 c. This embodiment illustrates an example in which the arcuate length L4 of the first lubrication pocket 1391 a is longer than the length that is the sum of the arcuate length L2 of the second sub back pressure pocket 1325 b and the arcuate length L3 of the third sub back pressure pocket 1325 c. Accordingly, the upper surface of the corresponding vane 135 passing through the second sub back pressure pocket 1325 b and the third sub back pressure pocket 1325 c in the axial direction almost always slides laterally across the first lubrication pocket 1391 a.

The first lubrication passage 1391 b may be formed such that the first lubrication pocket 1391 a and the oil storage space 110 b of the casing 110 communicate with each other. For example, an upper end of the first lubrication passage 1391 b in the axial direction may communicate with the first lubrication pocket 1391 a through a bottom surface of the first lubrication pocket 1391 a, and a lower end of the first lubrication passage 1391 b in the axial direction may be immersed in the oil storage space 110 b of the casing 110 through a lower surface of the sub plate portion 1321 so as to communicate with the oil storage space 110 b. Accordingly, oil stored in the oil storage space 110 b of the casing 110 may be directly supplied to the first lubrication pocket 1391 a through the first lubrication passage 1391 b.

An inner diameter D4 of the first lubrication passage 1391 b may be larger than or equal to the inner diameter D3 of the first back pressure passage portion 1381. Accordingly, oil stored in the oil storage space 110 b of the casing 110 may quickly move into the first lubrication pocket 1391 a through the first lubrication passage 1391 b.

The second lubricating portion 1392 may include a second lubrication pocket 1392 a and a second lubrication passage 1392 b. The second lubrication pocket 1392 a is a portion substantially defining a space of the second lubricating portion 1392, and the second lubrication passage 1392 b is a portion for guiding oil to the second lubrication pocket 1392 a.

The second lubrication pocket 1392 a may be formed symmetrically with the first lubrication pocket 1391 a based on the roller 134. Accordingly, repetitive description of the second lubrication pocket 1392 a has been omitted.

The second lubrication passage 1392 b may be formed to connect an inner circumferential surface of the second lubrication pocket 1392 a and an outer circumferential surface of the second main back pressure pocket 1315 b or the third main back pressure pocket 1315 c facing it. This embodiment illustrates an example in which the second lubrication passage 1392 b extends from the second main back pressure pocket 1315 b to the second lubrication pocket 1392 a.

If the second lubrication passage 1392 b extends from the third main back pressure pocket 1315 c to the second lubrication pocket 1392 a, a volume of the third main back pressure pocket 1315 c is larger than a volume of the second main back pressure pocket 1315 b, which may be disadvantageous in increasing pressure of the third main back pressure pocket 1315 c. Accordingly, it may be advantageous that the second lubrication passage 1392 b is not connected to the third main back pressure pocket 1315 c and connected to the second main back pressure pocket 1315 b in order to secure the super discharge pressure (or second discharge pressure) of the third main back pressure pocket 1315 c.

In addition, as the second lubrication passage 1392 b is connected to the second main back pressure pocket 1315 b, oil in the second main back pressure pocket 1315 b may be supplied to the second lubrication pocket 1392 a. Accordingly, oil may be quickly supplied to the second lubrication pocket 1392 a without adding a separate lubrication passage.

As illustrated in the embodiment, when the second lubrication pocket 1392 a is connected to the second main back pressure pocket 1315 b by the second lubrication passage 1392 b, a width (no reference numeral given) and/or axial depth H4 of the second lubrication pocket 1392 a may be smaller than or equal to a width (no reference numeral given) and/or axial depth H2 of the second main back pressure pocket 1315 b.

For example, when the width and/or axial depth H4 of the second lubrication pocket 1392 a is larger than the width and/or axial depth H2 of the second main back pressure pocket 1315 b, oil in the second main back pressure pocket 1315 b may excessively flow out into the second lubrication pocket 1392 a through the second lubrication passage 1392 b. Then, an amount of oil to be supplied to the corresponding back pressure chamber 1344 may be decreased, and thereby the back pressure with respect to the corresponding vane 135 may be weakened. Therefore, it may be advantageous in term of back pressure that the width and/or axial depth H4 of the second lubrication pocket 1392 a is smaller than or equal to the width and/or axial depth H2 of the second main back pressure pocket 1315 b and/or the third main back pressure pocket 1315 c.

As described above, when the first lubricating portion 1391 is formed on the sub bearing 132 and the second lubricating portion 1392 is formed on the main bearing 131, respectively, an axial side surface of the corresponding vane 135, which passes through the second sub back pressure pocket 1325 b and the second main back pressure pocket 1315 b and the third sub back pressure pocket 1325 c and the third main back pressure pocket 1315 c, laterally slides across the first lubrication pocket 1391 a and the second lubrication pocket 1392 a. Accordingly, oil accommodated in the first lubrication pocket 1391 a and the second lubrication pocket 1392 a forms a wide and thick oil film between the axial side surface of the vane 135 passing through the first lubrication pocket 1391 a and the second lubrication pocket 1392 a and the sub sliding surface 1321 a and the main sliding surface 1311 a facing the axial side surface of the vane 135.

This may prevent a so-called ‘discontinuous sliding phenomenon’ that the axial side surface of the vane 135 temporarily stops and then slides due to being excessively in close contact with the sub sliding surface 1321 a and/or the main sliding surface 1311 a. Then, the vane 135 may slide smoothly along the vane slot 1343 so as to be prevented from chattering. This may also suppress an aggravation of collision force with the cylinder 133 due to the discontinuous sliding of the vane 135, thereby more effectively preventing wear of the vane 135 and/or the cylinder 133.

Hereinafter, another embodiment of a first lubricating portion and a second lubricating portion will be described. That is, in the previous embodiment, the first lubrication pocket and the second lubrication pocket are each formed as one long groove, but in some cases, at least one of the first lubrication pocket or the second lubrication pocket may be formed as a plurality of grooves.

FIG. 19 is a perspective view illustrating another embodiment of a lubricating portion in FIG. 15 . IG. 20 is a cross-sectional view of FIG. 19 .

Referring to FIGS. 19 and 20 , the basic configuration and operating effects of the vane rotary compressor according to this embodiment are almost the same as those of the previous embodiments. For example, the basic configuration of the main bearing 131, the sub bearing 132, the cylinder 133, the roller 134, and the vane 135 constituting the compression part in the vane rotary compressor according to this embodiment is substantially the same as those of the previous embodiment.

In addition, in the vane rotary compressor according to the embodiment, the main bearing 131 may include first, second, and third main back pressure pockets 1315 a, 1315 b, and 1315 c at predetermined distances along the circumferential direction, and the sub bearing 132 may include first, second, and third sub back pressure pockets 1325 a, 1325 b, and 1325 c) at predetermined distances along the circumferential direction. The main back pressure pockets 1315 a, 1315 b, and 1315 c and the sub back pressure pockets 1325 a, 1325 b, and 1325 c may be formed in the same way as the main back pressure pocket 1315 and the sub back pressure pocket 1325 of the previous embodiments.

In addition, the vane rotary compressor according to this embodiment may include a first back pressure passage portion 1381 and a second back pressure passage portion 1382, and these back pressure passage portions 1381 and 1382 may also be formed in the same manner as the back pressure passage portions 1381 and 1382 of the previous embodiments.

However, the vane rotary compressor according to this embodiment includes the first lubricating portion 1391 and the second lubricating portion 1392, but the first lubrication pocket 1391 a and/or the second lubrication pocket 1392 a may be formed as a plurality of grooves, unlike the previous embodiment of FIG. 15 . This embodiment illustrates an example in which the first lubrication pocket 1391 a is formed as a plurality of grooves and the second lubrication pocket 1392 a is formed as a single groove.

For example, as illustrated in FIG. 19 , the first lubrication pocket 1391 a may be divided into a plurality of grooves disposed at predetermined distances along the circumferential direction. In this case, each of the plurality of grooves configuring the first lubrication pocket 1391 a may be formed in a circular shape or a short arcuate shape.

In addition, the first lubrication passages 1391 b may independently communicate with the respective grooves of the first lubrication pocket 1391 a. In this case, one (first) end of the first lubrication passage 1391 b may directly communicate with the first lubrication pocket 1391 a and another (second) end may directly communicate with the oil storage space 110 b of the casing 110, as illustrated in the previous embodiment of FIG. 15 . Accordingly, oil stored in the oil storage space 110 b of the casing 110 may quickly move into the grooves of the first lubrication pocket 1391 a through the first lubrication passages 1391 b, respectively.

As described above, when the first lubrication pocket 1391 a is formed as the plurality of grooves, oil may be continuously supplied to the first lubrication pocket 1391 a. The oil then forms a wide and thick oil film on the entire sub sliding surface 1321 a over the first lubrication pocket 1391 a, thereby reducing friction loss between the vane 135 and the sub sliding surface 1321 a.

In addition, in this embodiment, as the first lubrication pocket 1391 a is shortened, an intersecting section, which is generated in the circumferential direction between the vane 135 and the first lubricating portion 1391 (precisely, the first lubrication pocket), is decreased. Thus, the vane 135 is more brought into contact with the flat sub sliding surface 1321 a in the circumferential direction, thereby reducing friction loss between the vane 135 and the sub sliding surface 1321 a.

Hereinafter, still another embodiment of a first lubricating portion and a second lubricating portion will be described. That is, the previous embodiments illustrate the lubrication pockets, but in some cases, a lubrication passage may be merely provided without a lubrication pocket.

FIG. 21 is a perspective view illustrating still another embodiment of the lubricating portion in FIG. 15 . FIG. 22 is a cross-sectional view of FIG. 21 .

Referring to FIGS. 21 and 22 , the basic configuration and operating effects of the vane rotary compressor according to this embodiment are almost the same as those of the previous embodiments. For example, the basic configuration of the main bearing 131, the sub bearing 132, the cylinder 133, the roller 134, and the vane 135 constituting the compression part in the vane rotary compressor according to this embodiment is substantially the same as those of the previous embodiment.

In addition, in the vane rotary compressor according to the embodiment, the main bearing 131 may include first, second, and third main back pressure pockets 1315 a, 1315 b, and 1315 c disposed at predetermined distances along the circumferential direction, and the sub bearing 132 may include first, second, and third sub back pressure pockets 1325 a, 1325 b, and 1325 c disposed at predetermined distances in the circumferential direction. These main back pressure pockets 1315 a, 1315 b, 1315 c and sub back pressure pockets 1325 a, 1325 b, 1325 c may be formed in the same way as the main back pressure pocket 1315 and the sub back pressure pocket 1325 of the previous embodiments.

In addition, the vane rotary compressor according to this embodiment may include first back pressure passage portion 1381 and second back pressure passage portion 1382, and these back pressure passage portions 1381 and 1382 may also be formed in the same manner as the back pressure passage portions 1381 and 1382 of the previous embodiments.

However, the vane rotary compressor according to this embodiment may include the first lubricating portion 1391 and the second lubricating portion 1392, but any one of the first lubricating portion 1391 and the second lubricating portion 1392 may merely include a lubrication passage. In this embodiment, an example in which the first lubricating portion 1391 includes a plurality of first lubrication passages 1391 b is illustrated. As the second lubricating portion 1391 is the same as that in the embodiment of FIG. 15 , it will be understood by the description of the embodiment of FIG. 15 .

The first lubricating portion 1391 according to this embodiment may include a plurality of first lubrication passages 1391 b. The plurality of first lubrication passages 1391 b may pass through the sub bearing 132 and communicate with the oil storage space 110 b of the casing 110. For example, an upper end of the first lubrication passage 1391 b in the axial direction may communicate with the sub sliding surface 1321 a and a lower end of the first lubrication passage 1391 b in the axial direction may be immersed in the oil storage space 110 b of the casing 110 through a lower surface of the sub plate portion 1321 so as to communicate with the oil storage space 110 b. Accordingly, oil stored in the oil storage space 110 b of the casing 110 may be directly supplied to the sub sliding surface 1321 a through the first lubrication passage 1391 b.

An inner diameter D4 of each of the plurality of first lubrication passages 1391 b may be larger than or equal to the inner diameter D3 of the first back pressure passage portion 1381. Accordingly, oil stored in the oil storage space 110 b of the casing 110 may be quickly supplied to the sub sliding surface 1321 a through the first lubrication passages 1391 b.

Also, the plurality of first lubrication passages 1391 b may be disposed at equal distances in the circumferential direction. The plurality of first lubrication passages 1391 b may have a same inner diameter or different inner diameters. For example, the inner diameter of the first lubrication passage 1391 b may be increased as it approaches the reference point P based on the rotational direction of the roller 134. In this embodiment, an example is shown in which the plurality of first lubrication passages 1391 b have the same inner diameter. Accordingly, the processing of the first lubrication passages 1391 b may be easy, and oil may be supplied to the sub sliding surface 1321 a almost uniformly.

As described above, even when the first lubricating portion 1391 includes only the plurality of first lubrication passages 1391 b, oil stored in the oil storage space 110 b of the casing 110 may be continuously supplied to the sub sliding surface 1321 a through the first lubrication passages 1391 b, and widely spread on the sub sliding surface 1321 a. Accordingly, even if the lubrication pocket 1391 a as in the previous embodiment is not formed in the sub sliding surface 1321 a, a wide and thick oil film may be formed on the sub sliding surface 1321 a, thereby lowering friction loss between the vane 135 and the sub sliding surface 1321 a. This may prevent discontinuous sliding of the vane 135, thereby suppressing chattering of the vane 135.

In addition, in the embodiment, as the first lubrication pocket 1391 a in the embodiments of FIGS. 15 and 19 is excluded, the intersecting section in the circumferential direction between the vane 135 and the first lubricating portion 1391 is much more shortened. Thus, the vane 135 is brought into contact with the substantially flat sub sliding surface 1321 a in the circumferential direction, thereby further reducing friction loss between the vane 135 and the sub sliding surface 1321 a.

Although not illustrated, the discharge port may be formed through the cylinder instead of the main bearing and the sub bearing. In this case as well, the vane support structure using the compression coil spring may be applied equally.

Embodiments disclosed herein describe a rotary compressor capable of reducing vibration noise due to chattering of vanes during an operation of the compressor. Embodiments disclosed herein also describe a rotary compressor capable of suppressing chattering of a vane by increasing force for pressing the vane passing near a reference point adjacent to a final discharge port toward a cylinder during an operation of the compressor.

Embodiments disclosed herein further describe a rotary compressor capable of suppressing uneven wear of a vane by applying uniform pressing force to the vane when the vane passes near a reference point during an operation of the compressor. Embodiments disclosed herein furthermore describe a rotary compressor, capable of enhancing efficiency of the compressor by suppressing a delay of an initial startup of the compressor.

Embodiments disclosed herein describe a rotary compressor capable of quickly performing an initial startup operation by suppressing a refrigerant leakage near a reference point during an operation of the compressor. Embodiments disclosed herein further describe a rotary compressor capable of further increasing efficiency of the compressor by reducing friction loss in other regions except for a region near a reference point while suppressing or preventing refrigerant leakage near the reference point during operation of the compressor.

Embodiments disclosed herein further describe a rotary compressor in which a vane may reciprocates continuously without interruption.

Embodiments disclosed herein further describe a rotary compressor capable of continuously reciprocating a vane by reducing friction loss between the vane and a main bearing and/or sub bearing facing the vane. Embodiments disclosed herein also disclose a rotary compressor capable of enhancing a lubricating effect by smoothly applying oil between a vane and a main bearing and/or sub bearing facing the vane. Embodiments disclosed herein additionally describe a rotary compressor capable of effectively suppressing chattering of vanes even when a high-pressure refrigerant, such as R32, R410a, or CO₂, is used.

Embodiments disclosed herein provide a rotary compressor that may include a casing, a drive motor, a rotational shaft, a cylinder, a roller, vanes, a main bearing, and a sub bearing. The drive motor may be disposed in an inner space of the casing. The rotational shaft may be coupled to a rotor of the drive motor, and an oil supplying passage may be formed in a hollow shape through an inside of the rotational shaft. The cylinder may be disposed in the inner space of the casing to define a compression space. The roller may be disposed on the rotational shaft and accommodated in the compression space. The roller may be eccentrically located with respect to an inner circumferential surface of the cylinder. The vanes may be slidably inserted into vane slots disposed in the roller. The main bearing and the sub bearing may be disposed on both sides of the cylinder in an axial direction to form the compression space together with the cylinder. At least one of the main bearing and the sub bearing may include a discharge port through which refrigerant compressed in the compression space is discharged to the inner space of the casing, and a plurality of back pressure pockets communicating with rear sides of the vanes are disposed at one side of the discharge port to be spaced apart from each other in a circumferential direction.

A back pressure pocket that is closest to the discharge port of the plurality of back pressure pockets may communicate with the inner space of the casing by a back pressure passage portion penetrating through at least one of the main bearing and the sub bearing. Accordingly, the back pressure pocket closest to the discharge port may strongly support a vane passing near a reference point adjacent to the discharge port toward a cylinder while forming discharge pressure or super discharge pressure higher than the discharge pressure. This may suppress pr prevent chattering of the vane near the reference point to reduce vibration noise, and simultaneously suppress wear between the vane and the cylinder to enhance compression efficiency. This may also suppress or prevent leakage between compression chambers, thereby preventing a delay of an initial startup of the compressor. Therefore, when the compressor is applied to an air conditioning apparatus, a delay of an air conditioning effect may be prevented.

Each of the main bearing and the sub bearing may include a bearing hole in which the rotational shaft is inserted and supported. The back pressure pocket closest to the discharge port may be radially spaced apart from an inner circumferential surface of the bearing hole so as to be isolated from the bearing hole. Hence, the back pressure pocket closest to the discharge port may form an almost sealed space and secure discharge pressure or back pressure higher than the discharge pressure, thereby strongly supporting the vane toward the cylinder.

The rotational shaft may include an oil supply passage formed therein in a hollow shape, and at least one oil supply hole formed in a penetrating manner from an inner circumferential surface of the oil supply passage to an outer circumferential surface of the rotational shaft. The back pressure passage portion may have an inner diameter smaller than or equal to an inner diameter of the oil supply hole. This may prevent an occurrence of an oil shortage in another back pressure pocket, which results from that oil suctioned through the oil supply passage excessively flows out through the back pressure passage portion.

The rotational shaft may include an oil supply passage formed therein in a hollow shape, and at least one oil supply hole formed in a penetrating manner from an inner circumferential surface of the oil supply passage to an outer circumferential surface of the rotational shaft. The back pressure passage portion may be located at one side of the oil supply hole in the axial direction. Accordingly, oil suctioned through the oil supply passage may quickly move to the back pressure passage portion, and simultaneously rigidity of the rotational shaft may be secured.

The back pressure passage portion may be formed to be eccentric from a center of the back pressure pocket to a reference point where the roller and the cylinder are closest to each other. With this configuration, the vane may block the back pressure passage portion at a position closest to the discharge port, so as to close the corresponding back pressure pocket and secure high back pressure.

The back pressure passage portion may be located at a position where the same periodically overlaps the vane during a reciprocating motion of the vane. Accordingly, the back pressure passage portion may be blocked periodically by the vane, such that the corresponding back pressure packet may form a closed space so as to secure high back pressure.

The back pressure passage portion may have an inner diameter smaller than a width of the vane. Accordingly, the back pressure passage portion may be blocked periodically by the vane, such that the corresponding back pressure packet may form a closed space so as to secure high back pressure.

The back pressure passage portion may include a first back pressure hole and a second back pressure hole. The first back pressure hole may penetrate from an inner circumferential surface of the oil supply passage to an outer circumferential surface of the rotational shaft. The second back pressure hole may be formed through at least one of the main bearing and the sub bearing to communicate with the first back pressure hole, so as to communicate with the back pressure pocket. Hence, high pressure oil may be introduced into the back pressure pocket closest to the discharge port by centrifugal force generated when the rotational shaft rotates.

More specifically, the second back pressure hole may have an inner diameter smaller than or equal to an inner diameter of the first back pressure hole. Accordingly, oil introduced into the back pressure pocket closest to the discharge port may be prevented from easily flowing out through the back pressure passage portion when the vane moves backward, thereby maintaining back pressure of the back pressure pocket.

Also, a communication groove may be formed between the first back pressure hole and the second back pressure hole. The communication groove may have a cross-sectional area that is larger than at least one of a cross-sectional area of the first back pressure hole and a cross-sectional area of the second back pressure hole. This may reduce processing errors for the back pressure passage portion while the back pressure passage portion is formed in each of the rotational shaft and the main and sub bearings, and also may prevent blocking of the back pressure passage portion such that oil may be smoothly supplied to the back pressure pocket.

More specifically, the communication groove may be formed in an arcuate shape so that the first back pressure hole and the second back pressure hole communicate with each other periodically. Accordingly, the back pressure passage portion may be periodically blocked during an operation of the compressor, and hence the corresponding back pressure pocket may periodically form a closed space so as to minimize oil leakage therefrom, thereby securing high back pressure.

Also, the communication groove may be formed in a circular shape so that the first back pressure hole and the second back pressure hole communicate with each other continuously. This may allow oil to be continuously supplied to the back pressure pocket closest to the discharge port without interruption, thereby preventing in advance back pressure from being weakened due to an oil shortage in the back pressure pocket.

The back pressure passage portion may have one (first) end communicating with the back pressure pocket closest to the discharge port, and another (second) end communicating with the inner space of the casing through at least one of the main bearing and the sub bearing. This may facilitate the formation of the back pressure passage portion and simultaneously allow oil to be quickly flow into the back pressure pocket.

The back pressure pocket closest to the discharge port among the plurality of back pressure pockets may have a volume smaller than a volume of another back pressure pocket. This may result in maintaining pressure of the back pressure pocket closest to the discharge port to be higher than pressure of the another back pressure pocket.

More specifically, the back pressure pocket closest to the discharge port among the plurality of back pressure pockets may have an arcuate length shorter than an arcuate length of the another back pressure pocket. Accordingly, the pressure of the back pressure pocket closest to the discharge port may be maintained to be higher than the pressure of the another back pressure pocket and simultaneously a section where the vane is in close contact with the cylinder may be minimized so as to suppress an increase in friction loss.

Also, the back pressure pocket closest to the discharge port among the plurality of back pressure pockets may have a depth smaller than a depth of the another back pressure pocket. This may result in easily maintaining pressure of the back pressure pocket closest to the discharge port to be higher than pressure of the another back pressure pocket.

A lubricating portion may be formed at at least one of the main bearing or the sub bearing radially outside the back pressure pocket. At least portion of the lubricating portion may radially overlap the back pressure pocket closest to the discharge port. Hence, the vane may be in close contact with the main bearing and/or the sub bearing, which may suppress an occurrence of discontinuous sliding of the vane and reduce chattering of the vane at the same time, thereby enhancing compression efficiency and reliability.

More specifically, the lubricating portion may include a lubrication pocket and a lubrication passage. The lubrication pocket may be spaced apart from the back pressure pocket. The lubrication passage may connect the lubrication pocket and the inner space of the casing to guide oil stored in the inner space of the casing to the lubrication pocket. Thus, the oil stored in the inner space of the casing may be quickly supplied to the lubrication pocket, so as to form a wide and thick oil film between the vane and the bearing surface facing the same.

Also, the lubrication pocket may be configured as one groove extending in the circumferential direction. The lubrication passage may be provided as one or more in number in the circumferential direction of the lubrication pocket. This may increase a circumferential length of the lubrication pocket in contact with the vane, which may result in quickly and uniformly forming an oil film on the vane and the bearing surface facing the vane.

Also, the lubrication pocket may be provided as a plurality spaced apart from each other in the circumferential direction. The lubrication passage may independently communicate with each of the plurality of lubrication pockets. This may decrease a circumferential length of the lubrication pocket, which may result in reducing friction loss between the vane and the lubrication pocket that crosses with respect to a reciprocating direction of the vane.

Also, the lubricating portion may include at least one lubrication passage formed through the sub bearing. The lubrication passage may have one (first) end open toward the vane at one (first) axial side surface of the sub bearing, and another (second) end open toward the inner space of the casing at another (second) axial side surface of the sub bearing. This may facilitate formation of the lubricating portion and further shorten the circumferential length of the lubrication pocket, which may result in reducing friction loss between the vane and the lubrication pocket that crosses with respect to a reciprocating direction of the vane.

Also, the lubricating portion may include a lubrication pocket and a lubrication passage. The lubrication pocket may be spaced apart from the back pressure pocket. The lubrication passage may extend from at least one of the back pressure pockets excluding the back pressure pocket closest to the discharge port to communicate with the lubrication pocket. This may facilitate e formation of the lubricating portion and minimize an oil supplying length of the lubricating portion such that oil may be quickly supplied between the vane and the bearing.

More specifically, an axial depth of the lubrication pocket may be smaller than or equal to an axial depth of the back pressure pocket to which the lubrication pocket is connected. This may suppress or prevent oil of the back pressure pocket from excessively flowing to the lubrication pocket, thereby appropriately maintaining the back pressure of the back pressure pocket.

It will be understood that when an element or layer is referred to as being “on” another element or layer, the element or layer may be directly on another element or layer or intervening elements or layers. In contrast, when an element is referred to as being “directly on” another element or layer, there are no intervening elements or layers present. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

It will be understood that, although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.

Spatially relative terms, such as “lower”, “upper” and the like, may be used herein for ease of description to describe the relationship of one element or feature to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “lower” relative to other elements or features would then be oriented “upper” relative to the other elements or features. Thus, the exemplary term “lower” may encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Embodiments are described herein with reference to cross-section illustrations that are schematic illustrations of idealized embodiments (and intermediate structures). As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments may be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art. 

What is claimed is:
 1. A rotary compressor, comprising: a drive motor disposed in an inner space of a casing; a rotational shaft coupled to a rotor of the drive motor; a cylinder disposed in the inner space of the casing to define a compression space; a roller disposed on the rotational shaft and accommodated in the compression space, to be eccentric with respect to an inner circumferential surface of the cylinder; a plurality of vanes slidably inserted, respectively, into a plurality of vane slots provided in the roller; and a main bearing and a sub bearing, respectively, disposed on both sides of the cylinder in an axial direction to define the compression space together with the cylinder, wherein at least one of the main bearing or the sub bearing includes at least one discharge port through which refrigerant compressed in the compression space is discharged to the inner space of the casing, wherein a plurality of back pressure pockets that communicates with rear sides of the plurality of vanes is disposed at one side of the at least one discharge port spaced apart from each other in a circumferential direction, and wherein a first back pressure pocket, which is closest to the at least one discharge port of the plurality of back pressure pockets, communicates with the inner space of the casing via a back pressure passage that penetrates through at least one of the main bearing or the sub bearing.
 2. The rotary compressor of claim 1, wherein each of the main bearing and the sub bearing includes a bearing hole into which the rotational shaft is inserted and supported, and wherein the first back pressure pocket is radially spaced apart from an inner circumferential surface of the bearing hole so as to be isolated from the bearing hole.
 3. The rotary compressor of claim 1, wherein the rotational shaft includes an oil supply passage formed therein, and at least one oil supply hole that extends from an inner circumferential surface of the oil supply passage to an outer circumferential surface of the rotational shaft, and wherein the back pressure passage has an inner diameter smaller than or equal to an inner diameter of the oil supply hole.
 4. The rotary compressor of claim 1, wherein the rotational shaft includes an oil supply passage formed therein, and at least one oil supply hole that extends from an inner circumferential surface of the oil supply passage to an outer circumferential surface of the rotational shaft, and wherein the back pressure passage is located at one side of the oil supply hole in the axial direction.
 5. The rotary compressor of claim 1, wherein the back pressure passage is eccentric from a center of the first back pressure pocket to a reference point at which the roller and the cylinder are closest to each other.
 6. The rotary compressor of claim 1, wherein the back pressure passage portion is located at a position at which it periodically overlaps a vane of the plurality of vanes during a reciprocating motion of the vane.
 7. The rotary compressor of claim 6, wherein the back pressure passage has an inner diameter smaller than a width of the vane.
 8. The rotary compressor of claim 1, wherein the rotational shaft includes an oil supply passage formed therein, and wherein the back pressure passage comprises: a first back pressure hole formed in a penetrating manner from an inner circumferential surface of the oil supply passage to an outer circumferential surface of the rotational shaft; and a second back pressure hole formed through at least one of the main bearing or the sub bearing to communicate with the first back pressure hole and the back pressure pocket.
 9. The rotary compressor of claim 8, wherein the second back pressure hole has an inner diameter smaller than or equal to an inner diameter of the first back pressure hole.
 10. The rotary compressor of claim 8, wherein a communication groove is formed between the first back pressure hole and the second back pressure hole, and wherein the communication groove has a cross-sectional area larger than at least one of a cross-sectional area of the first back pressure hole or a cross-sectional area of the second back pressure hole.
 11. The rotary compressor of claim 10, wherein the communication groove is formed in an arcuate shape so that the first back pressure hole and the second back pressure hole communicate with each other periodically, or the communication groove is formed in a circular shape so that the first back pressure hole and the second back pressure hole communicate with each other continuously.
 12. The rotary compressor of claim 1, wherein a first end of the back pressure passage communicates with the first back pressure pocket and a second end of the back pressure passage communicates with the inner space of the casing through at least one of the main bearing or the sub bearing.
 13. The rotary compressor of claim 1, wherein the first back pressure pocket has a volume smaller than a volume of a second back pressure pocket of the plurality of back pressure pockets.
 14. The rotary compressor of claim 13, wherein the first back pressure pocket has an arcuate length shorter than an arcuate length of the second back pressure pocket, or the first back pressure pocket has a depth smaller than a depth of the second back pressure pocket.
 15. The rotary compressor of claim 1, wherein a lubrication portion is formed at at least one of the main bearing or the sub bearing radially outside of the first back pressure pocket, and wherein at least a portion of the lubrication portion radially overlaps the first back pressure pocket.
 16. The rotary compressor of claim 15, wherein the lubrication portion comprises: at least one lubrication pocket spaced apart from the first back pressure pocket; and at least one lubrication passage that connects the at least one lubrication pocket and the inner space of the casing to guide oil stored in the inner space of the casing to the at least one lubrication pocket, wherein the at least one lubrication pocket is configured as a groove that extends in the circumferential direction, and wherein the at least one lubrication passage comprises one or more lubrication passage in the circumferential direction of the at least one lubrication pocket.
 17. The rotary compressor of claim 15, wherein the lubrication portion comprises: at least one lubrication pocket spaced apart from the first back pressure pocket; and at least one lubrication passage that connects the at least one lubrication pocket and the inner space of the casing to guide oil stored in the inner space of the casing to the at least one lubrication pocket, wherein the at least one lubrication pocket comprises a plurality of lubrication pockets spaced apart from each other in the circumferential direction, and wherein the at least one lubrication passage independently communicates with each of the plurality of lubrication pockets.
 18. The rotary compressor of claim 15, wherein the lubrication portion comprises at least one lubrication passage formed through the sub bearing, and wherein a first end of the at least one lubrication passage is open toward a vane of the plurality of vanes at a first axial side surface of the sub bearing, and a second end is open toward the inner space of the casing at a second axial side surface of the sub bearing.
 19. The rotary compressor of claim 15, wherein the lubrication portion comprises: at least one lubrication pocket spaced apart from the first back pressure pocket; and at least one lubrication passage that extends from at least one of the plurality of back pressure pockets, excluding the first back pressure pocket, to communicate with the at least one lubrication pocket.
 20. The rotary compressor of claim 19, wherein an axial depth of the at least one lubrication pocket is smaller than or equal to an axial depth of the back pressure pocket to which the at least one lubrication pocket is connected.
 21. A rotary compressor, comprising: a drive motor disposed in an inner space of a casing; a rotational shaft coupled to a rotor of the drive motor; a cylinder disposed in the inner space of the casing to define a compression space; a roller disposed on the rotational shaft and accommodated in the compression space, to be eccentric with respect to an inner circumferential surface of the cylinder; a plurality of vanes slidably inserted, respectively, into a plurality of vane slots provided in the roller; and a main bearing and a sub bearing, respectively, disposed on both sides of the cylinder in an axial direction to define the compression space together with the cylinder, wherein at least one of the main bearing or the sub bearing includes at least one discharge port through which refrigerant compressed in the compression space is discharged to the inner space of the casing, wherein a plurality of back pressure pockets that communicates with rear sides of the plurality of vanes is disposed at one side of the at least one discharge port spaced apart from each other in a circumferential direction, wherein a first back pressure pocket, which is closest to the at least one discharge port of the plurality of back pressure pockets, communicates with the inner space of the casing via a back pressure passage that penetrates through at least one of the main bearing or the sub bearing and the rotational shaft, and wherein the back pressure passage is eccentric from a center of the first back pressure pocket to a reference point at which the roller and the cylinder are closest to each other.
 22. A rotary compressor, comprising: a drive motor disposed in an inner space of a casing; a rotational shaft coupled to a rotor of the drive motor; a cylinder disposed in the inner space of the casing to define a compression space; a roller disposed on the rotational shaft and accommodated in the compression space, to be eccentric with respect to an inner circumferential surface of the cylinder; a plurality of vanes slidably inserted, respectively, into a plurality of vane slots provided in the roller; and a main bearing and a sub bearing, respectively, disposed on both sides of the cylinder in an axial direction to define the compression space together with the cylinder, wherein at least one of the main bearing or the sub bearing includes at least one discharge port through which refrigerant compressed in the compression space is discharged to the inner space of the casing, wherein a plurality of back pressure pockets that communicates with rear sides of the plurality of vanes is disposed at one side of the at least one discharge port spaced apart from each other in a circumferential direction, wherein a first back pressure pocket, which is closest to the at least one discharge port of the plurality of back pressure pockets, communicates with the inner space of the casing via a back pressure passage that penetrates through at least one of the main bearing or the sub bearing, wherein the rotational shaft includes an oil supply passage formed therein, and wherein the back pressure passage comprises: a first back pressure hole that extends from an inner circumferential surface of the oil supply passage to an outer circumferential surface of the rotational shaft; a second back pressure hole formed through at least one of the main bearing or the sub bearing to communicate with the first back pressure hole and the first back pressure pocket; and a communication groove formed between the first back pressure hole and the second back pressure hole. 